Data Access Object (DAO)

# The Data Access Object (DAO) support in Spring is aimed at making it easy to
  work with data access technologies like JDBC,   Hibernate, JPA (our one JPA) or JDO in a consistent way

# The best way to guarantee that your Data Access Objects (DAOs) or
  repositories provide exception translation is to use the @Repository annotation

# Any DAO or repository implementation will need to access to a persistence resource,
 depending on the persistence technology used; for example, a JDBC-based repository will
 need access to a JDBC DataSource; a JPA - based repository will need access to an EntityManager.
 The easiest way to accomplish this is to have this resource dependency injected using one of
 the @Autowired,, @Inject,@Resource or @PersistenceContext annotations.

 @Autowired
 EntityManager em;

# return em.createNativeQuery(sql).getResultList();

# Query query = em.createNativeQuery(sql);
  BigDecimal exChangeRate = (BigDecimal)query.getSingleResult();

Views - SQL

Benifits  of   Views   

A view provides several benefits.

1. Views can hide complexity

If you have a query that requires joining several tables, or has complex logic or calculations,
you can code all that logic into a view, then select from the view just like you would a table.

2. Views can be used as a security mechanism

A view can select certain columns and/or rows from a table, and permissions set on the view
instead of the underlying tables. This allows surfacing only the data that a user needs to see.

3. Views can simplify supporting legacy code

If you need to refactor a table that would break a lot of code, you can replace the table
with a view of the same name. The view provides the exact same schema as the original table,
while the actual schema has changed. This keeps the legacy code that references the table
from breaking, allowing you to change the legacy code at your leisure.


4.Among other things, it can be used for security. If you have a "customer" table, you might
want to give all of your sales people access to the name, address, zipcode, etc. fields, but
not credit_card_number. You can create a view that only includes the columns they need access
 to and then grant them access on the view.

5.A view is an encapsulation of a query. Queries that are turned into views tend to be complicated
 and as such saving them as a view for reuse can be advantageous.  Though a view doesn't store data, some refer to a views as “virtual tables,” you can query a view like you can a table .

6.Once a view is created you can used then as you would any table in a SELECT statement.

7.Views take up very little space, as the data is stored once in the source table.

Sample  view  is  shown  below .

 

CREATE OR REPLACE VIEW    SAMPLE_VIEW     AS
SELECT  cast('A' as varchar2(2)) col1,'Overdue period > 0  month and < 3 months' col2
FROM dual
UNION
SELECT cast('B' as varchar2(2)) col1,'Overdue period > 3  month and < 6 months' col2
FROM dual
UNION
SELECT cast('C' as varchar2(2))  col1,'Overdue period >= 24 months' col2
FROM dual
UNION
SELECT cast('D' as varchar2(2))  col1, 'Overdue RV > 0'  col2
FROM dual

Worth to Read

• Step By Step Path to Becoming a Great Software Developer

  10 Life Lessons , Learned in Last Few Years 

How to Rock a Side Project When You Have No Free Time (Extracted From StackOverflow ,Author Alyssa Mazzina)

We’ve all heard the advice: the best developers live and breathe programming. But you’re also a human being. Maybe you’re not the stereotypical 22-year-old with no ties or responsibilities, happy to work 18-hour days. Maybe you’re a mother or a father, a husband or a wife, a caretaker of an elderly relative.
There are millions of developers in the world, and they come in every shape. Most of us are not in our early 20s, many of us aren’t single, and few of us want to give our entire lives to our jobs. So how do we reconcile that truth with the general belief that the “best” developers are those who eat, sleep, and breathe code?
In other words, how can you show you’re passionate and committed without completely neglecting the rest of your life and responsibilities? Specifically, how can you find the time for personal projects without losing your mind?

I spoke with a few developers who face this challenge every day. These are people with full-time jobs, families, and busy non-work lives who have also built and continue to build successful side projects. There’s no magic bullet, they insist. It’s a matter of priorities and accountability. Here’s how they do it without destroying their lives in the process.

Why do developers build on the side?

Keeping skills sharp

Max Page, a lead developer turned product manager, values the opportunity to work on his side project CouponHippo because it helps him keep his coding skills fresh now that he’s not using them like he used to in his day job. “My main goals for this work,” he says, “are to keep my coding skills sharp, play with new technologies that come out, and to augment my normal income if possible.”

Additional income

A secondary income stream is a driving factor for many developers who work on personal projects outside of work. Craig Phares runs his own digital agency, Six Overground, full time, but also works on smaller projects (here’s one example) outside the scope of his client work. “As a digital agency,” he says, “we’re often tied very closely to an hourly rate, so to make more money you have to work more hours. Building a product that brings in revenue without a direct relation to hours is ideal and fills in those inevitable slow periods of client work.”

New technologies, new opportunities

Craig also values the non-monetary benefits of side work. “Side projects are a great opportunity to learn a new technology. My first Ruby on Rails web application was a side project. My first native mobile app was a side project. Because you have the luxury of taking the time to experiment, you can really advance your technical chops.”
Developer Neil Harris built Intently.co as a side project while also working full-time as tech lead for a UK engineering company. Intently.co is growing quickly, and he expects it to become a full-time venture soon, but he maintains that building it “on the side” was of great value. “I wanted to build something without any investment, and this was the best way—my job gives me the financial stability to try new ventures on the side.”
Neil adds that it’s opened doors in his career. “I am now much more adept and confident with web technologies than I was before, and this gives me the confidence to lead teams in this space at work. Perhaps the most exciting opportunity is the chance to advise other startups or companies who want to grow their web presence—I have learnt a huge amount about hosting, SEO, and web apps because I have made a success of Intently.co, and I think it gives me the credentials to go and advise other companies.”
Stephan Baker, a software engineer at Forest Giant, agrees: “I don’t really go into these projects expecting it to open doors, but without a doubt it has on many occasions. Side projects, as well as attending developer events such as meetups and conferences, can really help to grow your professional network. Finding other people who are excited about the things you are excited about opens many doors, both personally and professionally.”
Justin Avdich, a Web Developer at Cheeky Monkey Media, says his side project is a passion project, and notes the benefits of building a reputation. It “helps me learn new skills and stay on top of some of the trends,” he says. “It’s also a way for me to put my work out in the wild for people to see.”
We’ve written before about building reputation and getting your work out there for people to see, and the developers I talked to agreed that side projects are an ideal way to do that. “Most technology jobs like people who have side projects,” says Max. “It shows you don’t just mail it in 9-5. You actually enjoy pushing yourself and using new technology. It shows passion.”

Passion

Passion is a main driver of side projects, and often times that passion comes from wanting to address a roadblock you’ve stumbled across in your daily life. Liza Rodewald, a .NET developer for the Mississippi Secretary of State’s office, cofounded a company called MadSkills on the side to fix a difficult issue she experienced: “I starting working on this project to solve a business problem I came across as a military spouse. There were professional spouses struggling to find meaningful professional work due to the frequent moves required by the military. MadSkills is my passion project.”
Unfortunately, some employers equate “you’re passionate about coding” with “you code in your free time.” While this is unfair assumption, developers who do have a side project can use it as a tangible and demonstrable example of loving their craft.

How do they find the time?

Keep it fun

In fact, passion was a recurring theme with the developers I spoke with. Most of them, when asked how they find or make time for side projects while they’re working full-time, raising families, or fulfilling other obligations, cite passion before anything else. Justin, who has both a full-time job and a 10-month-old daughter, says, “I feel that if you’re passionate about something, and enjoy doing it, it becomes easy to find the time. I treat it as a hobby, more of an escape than actual work.”
Adam Richardson of Forest Giant agrees. “I think it’s crucial to try to keep the job fun. Maybe what you’re working on at your day job isn’t your favorite and you feel totally drained once you’re done. This is understandable, but I think a powerful tool to fight burnout is continually seeking out, independently, things you find exciting and interesting.”

Prioritize and schedule

Doug Bradley, owner of Inland Empire Lawyers (which he built on the side while working full-time as a software developer for another firm), stresses the importance of being realistic. “Anyone that thinks building a side business is something you can do in your spare time is kidding themselves. There’s no such thing as spare time.” Rather, he argues, you can find the time if you’re truly passionate about something by prioritizing that over other things. “If you have no passion for it, then you’ll find no value or sense of pride trading your personal and family time to develop it properly.” Watching TV was the most commonly cited activity that developers forego in favor of coding.
Liza, raising four children with a husband in the military who is gone often, says, “I schedule every aspect of my life in order to create time for everything. I hire in-home childcare and household cleaning to help maximize my time. Everything in my life functions according to a plan. Laundry, groceries, family play time and work all get a schedule.”
Craig is blunt: “Replace ‘I don’t have time for this’ with ‘This isn’t a priority for me.’ Anyone can make time for something if it’s a priority… stop talking about it and start making it.”
One technique developers cite for “making” or “finding” time is setting aside a block of time—even a very small one—every day and holding yourself accountable. Milen Marinov, Lead Mobile Developer at Kanbanize, has built an app on the side called Help A Paw that “helps volunteers coordinate their efforts in helping injured stray animals.” Milen reminds us, “We all get 24 hours every day and having the time to do something is just a matter of priorities. So, if you feel your contribution will really help make other people’s (or animals’) lives better, you’ll find the time to do it!”
Overall, these developers felt that finding time to work on side projects wasn’t as difficult as many of us think it will be. Finding something you’re passionate about, holding yourself accountable, and scheduling hard blocks of time that you’re committed to spending on your project will all help you make progress on a side project.

Ship it. Now.

Most of the developers I spoke with stressed the importance of just shipping. Stephan says, “Whatever it is you’re making, remember that development is an iterative process. What you are making doesn’t have to be perfect the first time through, it isn’t going to be everyone’s cup of tea, and you shouldn’t wait until it’s finished to show someone what you’ve been doing (hint: It’s never really finished.”

Ethan Schmidt, who built GymBull.com with friends while working full-time as a software developer for the Department of Defense, agrees. “Don’t wait until you’re 100% comfortable with either technology or your business idea because by the time that you are, someone else will have made what you want and the whole community will be using a different set of tools.”
Neil says, “Jump in—if you have an idea then you can build it.” And Max advises finding a problem that people have (preferably all people, not just other developers, he emphasizes). Next, you should build “a small solution in a weekend and push it out live. Once something is live usually people find small amounts of time to incrementally make it better. Just take that first step, and it’s easier to keep going.”

Don’t forget about open source

Jesse Lucas, CTO of Forest Giant, advocates dabbling in the open source world, something we’ve also mentioned before here. “Don’t wait to be asked to help or join,” he advises. “Find something you’re interested in and start helping. The open source community is extremely helpful and inclusive. Don’t be afraid to put yourself out there and start contributing!”
This is also a way you can get involved and show your passion without diving in fully to building an entire product on your own. Just getting your feet wet by helping with somebody else’s project is a good start, and for some developers, that’s enough side work to keep their skills fresh and their network growing. Even if you don’t have a Big Idea, there is work to be done that you can do. And then you can put it on your resume.

Is it worth the sacrifices?

All of the developers I talked to about this felt strongly that working on side projects had benefited their careers and their lives; none of them regretted the time they’d spent on their projects. They all have full-time jobs, and most have spouses, children, and other obligations, but they all maintain that prioritizing a side project, starting small, and keeping the work fun help them push forward and accomplish great things “on the side.”
Julia Silge, a Data Scientist here at Stack Overflow, told me that getting involved in open source helped her transition into data science after spending a few years caring for her children full-time. “I got involved in open source thinking I would learn and update my skills,” she says, “but the network I’ve built has been invaluable to my career.”
Don’t waste what little time you have on things that aren’t worth the sacrifice; chances are, you have plenty of those things in your life, sucking up minutes here and there. A little discipline and prioritizing can help you make those minutes productive and rewarding.

Liza says, “I have a passion to see other professional women balance their families and continue their careers.” This passion drives her to find the time, and she finds it rewarding. “If I can juggle two jobs, four kids, and a husband in the military that’s gone all the time, the sky’s the limit.”
Craig, who is married with two young children, acknowledges the difficulties in balancing his priorities. “I pick up the kids from school every day, and cook dinner for my family,” he says. “And client work always takes priority over side projects. Yet, I’ve been able to build and launch a number of side projects.” He works late at night, when the kids are asleep, and gives himself strict deadlines. “It’s important to do a little bit each day,” he says, “even if it’s just an hour.”
He also acknowledges the importance of a supportive partner. “Having a partner’s support can be incredibly encouraging,” he says, noting that he can bounce ideas off his wife for feedback. “It’s important to make sure [your work] doesn’t infringe upon your personal relationships or family obligations…Friday and Saturday nights, there’s a no-work policy in our house.”
Justin’s wife, too, supports his efforts. “Without her support, it wouldn’t really be possible. I feel it’s important for a relationship to spend time doing things we both enjoy (sometimes it’s something together, sometimes it’s something individual).”
“Building and launching your own product can be an incredibly fulfilling experience,” says Craig. “And once you launch your first side project, you’ll be back for more.”

A word of caution

One thing the developers I spoke to agreed on was the importance of keeping your employer’s time and your own time separate. If you’re doing work on the side, it must actually be on the side—not snuck in at the office, or done when you should be working for a client.
Craig says he has a policy of “Funday Fridays, where everyone is allowed to work on their own side projects. Of course, if there’s a deadline for client work, that takes precedence, but having that day informally set aside to work on personal projects allows for an extended period of serious progress each week.” You might be surprised how many companies will allow some of this. But of course, many do not, and expect you to be on task for 40 hours per week, no exceptions. If this is the type of company you work for, don’t cross any lines.
You should also be aware that some contracts include clauses stipulating that if you DO build anything on company time, the company then owns the result (and any profit that comes from it). See what Stack Overflow CEO Joel Spolsky has to say about this.
The developers I talked to all agreed it is possible to find legitimate “free” time, even in the busiest lives, if you prioritize that time—and you shouldn’t have to short-change your employer to do it.

Your turn

I’d love to hear from you, the reader: do you have a side project? If not, why not? And what other information on side projects can I bring you to help you succeed



Link to  Original Post  :-  

How to Rock a Side Project When You Have No Free Time By Alyssa Mazzina

Comments in Different Programming Languages

#Java

             // single  line  comment

             /*

                      multiple 

                      line 

                      comment

             */

#JavaScript 

#JSP 

     <%-- comment --%>

#HTML

             <!-- comment -->

#SQL

            --comment

HTML DOM Events

HTML DOM Events

HTML DOM events allow JavaScript to register different event handlers on elements in an HTML document.
Events are normally used in combination with functions, and the function will not be executed before the event occurs (such as when a user clicks a button).
Tip: The event model was standardized by the W3C in DOM Level 2.

---

HTML DOM Events

DOM: Indicates in which DOM Level the property was introduced.

Mouse Events

Event	Description	DOM
onclick	The event occurs when the user clicks on an element	2
oncontextmenu	The event occurs when the user right-clicks on an element to open a context menu	3
ondblclick	The event occurs when the user double-clicks on an element	2
onmousedown	The event occurs when the user presses a mouse button over an element	2
onmouseenter	The event occurs when the pointer is moved onto an element	2
onmouseleave	The event occurs when the pointer is moved out of an element	2
onmousemove	The event occurs when the pointer is moving while it is over an element	2
onmouseover	The event occurs when the pointer is moved onto an element, or onto one of its children	2
onmouseout	The event occurs when a user moves the mouse pointer out of an element, or out of one of its children	2
onmouseup	The event occurs when a user releases a mouse button over an element	2

Keyboard Events

Event	Description	DOM
onkeydown	The event occurs when the user is pressing a key	2
onkeypress	The event occurs when the user presses a key	2
onkeyup	The event occurs when the user releases a key	2

Frame/Object Events

Event	Description	DOM
onabort	The event occurs when the loading of a resource has been aborted	2
onbeforeunload	The event occurs before the document is about to be unloaded	2
onerror	The event occurs when an error occurs while loading an external file	2
onhashchange	The event occurs when there has been changes to the anchor part of a URL	3
onload	The event occurs when an object has loaded	2
onpageshow	The event occurs when the user navigates to a webpage	3
onpagehide	The event occurs when the user navigates away from a webpage	3
onresize	The event occurs when the document view is resized	2
onscroll	The event occurs when an element's scrollbar is being scrolled	2
onunload	The event occurs once a page has unloaded (for <body>)	2

Form Events

Event	Description	DOM
onblur	The event occurs when an element loses focus	2
onchange	The event occurs when the content of a form element, the selection, or the checked state have changed (for <input>, <keygen>, <select>, and <textarea>)	2
onfocus	The event occurs when an element gets focus	2
onfocusin	The event occurs when an element is about to get focus	2
onfocusout	The event occurs when an element is about to lose focus	2
oninput	The event occurs when an element gets user input	3
oninvalid	The event occurs when an element is invalid	3
onreset	The event occurs when a form is reset	2
onsearch	The event occurs when the user writes something in a search field (for <input="search">)	3
onselect	The event occurs after the user selects some text (for <input> and <textarea>)	2
onsubmit	The event occurs when a form is submitted	2

Drag Events

Event	Description	DOM
ondrag	The event occurs when an element is being dragged	3
ondragend	The event occurs when the user has finished dragging an element	3
ondragenter	The event occurs when the dragged element enters the drop target	3
ondragleave	The event occurs when the dragged element leaves the drop target	3
ondragover	The event occurs when the dragged element is over the drop target	3
ondragstart	The event occurs when the user starts to drag an element	3
ondrop	The event occurs when the dragged element is dropped on the drop target	3

Clipboard Events

Event	Description	DOM
oncopy	The event occurs when the user copies the content of an element
oncut	The event occurs when the user cuts the content of an element
onpaste	The event occurs when the user pastes some content in an element

Print Events

Event	Description	DOM
onafterprint	The event occurs when a page has started printing, or if the print dialogue box has been closed	3
onbeforeprint	The event occurs when a page is about to be printed	3

Media Events

Event	Description	DOM
onabort	The event occurs when the loading of a media is aborted	3
oncanplay	The event occurs when the browser can start playing the media (when it has buffered enough to begin)	3
oncanplaythrough	The event occurs when the browser can play through the media without stopping for buffering	3
ondurationchange	The event occurs when the duration of the media is changed	3
onemptied	The event occurs when something bad happens and the media file is suddenly unavailable (like unexpectedly disconnects)	3
onended	The event occurs when the media has reach the end (useful for messages like "thanks for listening")	3
onerror	The event occurs when an error occurred during the loading of a media file	3
onloadeddata	The event occurs when media data is loaded	3
onloadedmetadata	The event occurs when meta data (like dimensions and duration) are loaded	3
onloadstart	The event occurs when the browser starts looking for the specified media	3
onpause	The event occurs when the media is paused either by the user or programmatically	3
onplay	The event occurs when the media has been started or is no longer paused	3
onplaying	The event occurs when the media is playing after having been paused or stopped for buffering	3
onprogress	The event occurs when the browser is in the process of getting the media data (downloading the media)	3
onratechange	The event occurs when the playing speed of the media is changed	3
onseeked	The event occurs when the user is finished moving/skipping to a new position in the media	3
onseeking	The event occurs when the user starts moving/skipping to a new position in the media	3
onstalled	The event occurs when the browser is trying to get media data, but data is not available	3
onsuspend	The event occurs when the browser is intentionally not getting media data	3
ontimeupdate	The event occurs when the playing position has changed (like when the user fast forwards to a different point in the media)	3
onvolumechange	The event occurs when the volume of the media has changed (includes setting the volume to "mute")	3
onwaiting	The event occurs when the media has paused but is expected to resume (like when the media pauses to buffer more data)	3

Animation Events

Event	Description	DOM
animationend	The event occurs when a CSS animation has completed	3
animationiteration	The event occurs when a CSS animation is repeated	3
animationstart	The event occurs when a CSS animation has started	3

Transition Events

Event	Description	DOM
transitionend	The event occurs when a CSS transition has completed	3

Server-Sent Events

Event	Description	DOM
onerror	The event occurs when an error occurs with the event source
onmessage	The event occurs when a message is received through the event source
onopen	The event occurs when a connection with the event source is opened

Misc Events

Event	Description	DOM
onmessage	The event occurs when a message is received through or from an object (WebSocket, Web Worker, Event Source or a child frame or a parent window)	3
onmousewheel	Deprecated. Use the onwheel event instead
ononline	The event occurs when the browser starts to work online	3
onoffline	The event occurs when the browser starts to work offline	3
onpopstate	The event occurs when the window's history changes	3
onshow	The event occurs when a <menu> element is shown as a context menu	3
onstorage	The event occurs when a Web Storage area is updated	3
ontoggle	The event occurs when the user opens or closes the <details> element	3
onwheel	The event occurs when the mouse wheel rolls up or down over an element	3

Touch Events

Event	Description	DOM
ontouchcancel	The event occurs when the touch is interrupted
ontouchend	The event occurs when a finger is removed from a touch screen
ontouchmove	The event occurs when a finger is dragged across the screen
ontouchstart	The event occurs when a finger is placed on a touch screen

Event Object

Constants

Constant	Description	DOM
CAPTURING_PHASE	The current event phase is the capture phase (1)	1
AT_TARGET	The current event is in the target phase, i.e. it is being evaluated at the event target (2)	2
BUBBLING_PHASE	The current event phase is the bubbling phase (3)	3

Properties

Property	Description	DOM
bubbles	Returns whether or not a specific event is a bubbling event	2
cancelable	Returns whether or not an event can have its default action prevented	2
currentTarget	Returns the element whose event listeners triggered the event	2
defaultPrevented	Returns whether or not the preventDefault() method was called for the event	3
eventPhase	Returns which phase of the event flow is currently being evaluated	2
isTrusted	Returns whether or not an event is trusted	3
target	Returns the element that triggered the event	2
timeStamp	Returns the time (in milliseconds relative to the epoch) at which the event was created	2
type	Returns the name of the event	2
view	Returns a reference to the Window object where the event occured	2

Methods

Method	Description	DOM
preventDefault()	Cancels the event if it is cancelable, meaning that the default action that belongs to the event will not occur	2
stopImmediatePropagation()	Prevents other listeners of the same event from being called	3
stopPropagation()	Prevents further propagation of an event during event flow	2

MouseEvent Object

Property	Description	DOM
altKey	Returns whether the "ALT" key was pressed when the mouse event was triggered	2
button	Returns which mouse button was pressed when the mouse event was triggered	2
buttons	Returns which mouse buttons were pressed when the mouse event was triggered	3
clientX	Returns the horizontal coordinate of the mouse pointer, relative to the current window, when the mouse event was triggered	2
clientY	Returns the vertical coordinate of the mouse pointer, relative to the current window, when the mouse event was triggered	2
ctrlKey	Returns whether the "CTRL" key was pressed when the mouse event was triggered	2
detail	Returns a number that indicates how many times the mouse was clicked	2
metaKey	Returns whether the "META" key was pressed when an event was triggered	2
pageX	Returns the horizontal coordinate of the mouse pointer, relative to the document, when the mouse event was triggered
pageY	Returns the vertical coordinate of the mouse pointer, relative to the document, when the mouse event was triggered
relatedTarget	Returns the element related to the element that triggered the mouse event	2
screenX	Returns the horizontal coordinate of the mouse pointer, relative to the screen, when an event was triggered	2
screenY	Returns the vertical coordinate of the mouse pointer, relative to the screen, when an event was triggered	2
shiftKey	Returns whether the "SHIFT" key was pressed when an event was triggered	2
which	Returns which mouse button was pressed when the mouse event was triggered	2

KeyboardEvent Object

Property	Description	DOM
altKey	Returns whether the "ALT" key was pressed when the key event was triggered	2
ctrlKey	Returns whether the "CTRL" key was pressed when the key event was triggered	2
charCode	Returns the Unicode character code of the key that triggered the onkeypress event	2
key	Returns the key value of the key represented by the event	3
keyCode	Returns the Unicode character code of the key that triggered the onkeypress event, or the Unicode key code of the key that triggered the onkeydown or onkeyup event	2
location	Returns the location of a key on the keyboard or device	3
metaKey	Returns whether the "meta" key was pressed when the key event was triggered	2
shiftKey	Returns whether the "SHIFT" key was pressed when the key event was triggered	2
which	Returns the Unicode character code of the key that triggered the onkeypress event, or the Unicode key code of the key that triggered the onkeydown or onkeyup event	2

HashChangeEvent Object

Property	Description	DOM
newURL	Returns the URL of the document, after the hash has been changed
oldURL	Returns the URL of the document, before the hash was changed

PageTransitionEvent Object

Property	Description	DOM
persisted	Returns whether the webpage was cached by the browser

FocusEvent Object

Property	Description	DOM
relatedTarget	Returns the element related to the element that triggered the event	3

AnimationEvent Object

Property	Description	DOM
animationName	Returns the name of the animation
elapsedTime	Returns the number of seconds an animation has been running

TransitionEvent Object

Property	Description	DOM
propertyName	Returns the name of the CSS property associated with the transition
elapsedTime	Returns the number of seconds a transition has been running

WheelEvent Object

Property	Description	DOM
deltaX	Returns the horizontal scroll amount of a mouse wheel (x-axis)	3
deltaY	Returns the vertical scroll amount of a mouse wheel (y-axis)	3
deltaZ	Returns the scroll amount of a mouse wheel for the z-axis	3
deltaMode	Returns a number that represents the unit of measurements for delta values (pixels, lines or pages)	3

Resource :-  w3schools

JavaScript Note

# DOM - document  object model
# var oldvlaue = document.getElementById("myID").value; //Getting
# document.getElementById("myId").value = "new value"   //Setting

#<p id=“myID"></p>
<script>document.getElementById("myID").innerHTML= “Let’s Learn DOM”;</script>

#<script>
var x = document.getElementById("title");
document.getElementById("myID").innerHTML="The value of element is " + x.innerHTML;
</script>

# element.addEventListener(event, function, useCapture);

# <body>
<button id="myBtn">click</button>
<script>
document.getElementById("myBtn").addEventListener("click", hello);
function hello() {
alert ("Hello World!");
}
</script>
</body>




#element.addEventListener("mouseover", FunctionOne);
element.addEventListener("click", FunctionTwo);
element.addEventListener("click", FunctionThree);
element.addEventListener("mouseout", FunctionFour);

# <body>
<script>
document.write(Date());
</script>
</body>



# <head>
<title>DOM Sample 1</title>
</head>
<body>
Information about this document.<br>
<script type="text/javascript">
document.write("<br>Title: ",document.title);
document.write("<br>Referrer: ",document.referrer);
document.write("<br>Domain: ",document.domain);
document.write("<br>URL: ",document.URL);
</script>
</body>


#DOM Events

#<html>
<head>
<title>DOM Sample</title>

<script type="text/javascript">
function showInfo() {var element = document.getElementById("opener");
var buffer = element.id + " tag is " + element.tagName;
alert(buffer);
element = document.getElementById("actionItem");
buffer = element.id + " tag is " + element.tagName;
buffer += ", type is "+element.type;alert(buffer);}
</script>

</head>
<body>
<p id="opener">The id attribute is very helpful.</p>
<p id="closer">This is the closing paragraph.</p>
<form><button id="actionItem" type="button" onclick="showInfo()">Show Info</button></form>
</body>
</html>


# Creating elements through Nodes
•Steps
1.Create the element (element node)
2.Append it to an existing element


#The HTML Document Object Model is a standard for structuring data on a web page


#  javaScript  born bcse , some data  has to validate at client  side
#  3 parts dom-  document  object model  -- node, bom ,ecma script

# DOM - Nodes cn be removed , added , replaced and  modifed easily
        Developers cn alter the appearance and content of a web page without  reloading it

# BOM - browser  object model

# Two ways to use the <script> elemnet
  #put javascript code directly into  page  within 
   tags
  #Include  javascript from other  file

#<script>  alert("What you want  to  print"); </script>

# Including External JS files ,the  src attribute is required .
# <script  type ="text/javascript" src = "example.js"></script>

#<script> elemnet  using  src attribute should  not  include  additional javaScript
code between  the  js code between  the <script> and </script> tags . iT is  ignored

# <script  src = "example.js"></script>


# The main purpose of this <script>  format  was to keep  to external file references,
both css files and javaScript files , in the  same area

#Including  js  in  <head>  means  that all the js  code must  be  downloaded , interpreted 
before the page begins rendering

#<script  tag  in  body element>

#Any  images and stylesheets that  follow the script tag dont start downloading until  script
has finished  downloading and executing
#A defer external script  will  start  downloading immediately but wont execute until  after  the
page is  rendered.

#DEFERRED SCRIPTS >>>> purpose  of  defer  is  to  indicate  that  a  script won't be changing
 the structure  of  the  page as it  executes.
 internal  file  structe  not chnged  but  external  may be

#defer atttribute  ona  a <script>  element  signals to  the  browser ,that  download  should  begin
immediately  but  execution  should be  deferred.

#even  though  the  <script>  elements  are  included  in  the  documnet  <head>  they  will  not   be  executed
until  after the  browser  has  received the  closing </html> tag.

# <script  type = "text/javascript" defer src = "example.js"></script>
# scripts  will  be executed  in  the  order in  which  they  appear
<script  type = "text/javascript" defer = "defer" src = "example.js"></script>
# the  defer , async attribute is supported only for external script files.........
# All old  browsers  , they  will  ignore  defer , so  it  is   still best to
  put deferred scripts  at the bottom of the page .

# The async attribute is similar to  defer ,in that it changes the way the script is processed.
# async = "async"

# Asynchronous execution - html parsing may continue and script will  be
executed as soon as it its ready .
# asnc  order is nt guaranteed

# Asynchrous  scripts are guaranteed to execute before the page's
 load  event and may execute  before or after DOMContentLoaded

# <script type ="text/javascript"  src = "javascript.js" async = "async"></script>

# inline code  vs  external  code >>>internal  scripts  are great  but , it  is  best  to  include
javascript using   external files  is  used  bcse  maintainalbility , caching - if two pages  are
using the  same file , the file is downloaded only once (this cause to faster  page loading)


# js  in xhtml  file  prob  fix 1 -  not goood  way
  < greater  sign  dosent  know  it
  replace all  occurences  of  the  less than symbol < with  its  , html entity (&lt;)
  a &lt; b
 
  <script type ="text/javascript">
   function compare(a,b)
   {
        if(a &lt; b)
    {
        alert("A is less than B");
         }
   }
   </script>

# js  in xhtml file   fix 2
  Wrap  the  javaScript  code in  a  CDATA section

  in XHTML  or  xml  , CDATA  sections   are  used to
  indicate ares used  to  indicate areas of  the document
  that contain free- from text not intended  to be parsed.

   <script type ="text/javascript">
   <![CDATA[
   function compare(a,b)
   {
        if(a &lt; b)
    {
        alert("A is less than B");
         }
   }
  ]]> </script>

..........this  part  will  be  ignore  by  html  parser ,  but  will  execute  by javaScript
CDATA[
   function compare(a,b)
   {
        if(a &lt; b)
    {
        alert("A is less than B");
         }
   }
  ]

..........

# js in xhtml  issues
  some browsers  complaint  to works in  xhtml

  if browser dont  support  CDATA  sections, CDATA  markup must
  be offset  by  javaScript  commnets .
 That  foramt  works in  all  modern  browsers

 <script type ="text/javascript">
  // <![CDATA[
   function compare(a,b)
   {
        if(a &lt; b)
    {
        alert("A is less than B");
         }
   }
 // ]]>
</script>

#By  inculding JavaScript  using  external files , there's no need to  use the xhtml
or comment hacks mentioned  previously.

# JavaScript  comments  
  single  line comment   // 
  multiline comment      /*    */
# JavaScript is  case  sentitive
# typeof  is  a  key word in  javaScript , you cnt  use  it  as name  of  a function.

# identifier = name of a variable , function , property  or function  argument .
# identifier's  name first  character must  be  a  letter , _  or  $  sign . All other 
  character may be letters , underscores , dollar signs or numbers.Use  camal  case .For  First
  word first leter use simple letter . 
  eg:- numberOne
# Statements  in  ECMAScript are  terminated  by a  semicolon .
  ommiting  the   semicolon makes parser  determine  whether  the end of  a  statement  occurs
 .It  is  not  recommonded.
  Semicolons may improve performance because parsers  try to correct syntax errors by inserting
  semicolons where they appear  to be .

            

# document.write(samp_str + "<br/>");
  document.write("String  Variable  finally Length  is" + stringVar.length + "<br/>");
  document.write("String  Variable  substring  " + stringVar.substring(6,12) + "<br/>" );
  document.write("SFinal  letter" + stringVar.charAt(stringVar.length - 1)  + "<br/>");
  document.write("Index  of T is " + stringVar.indexOf('t') + "<br/>") ;

# String cant  be  multiplied  , if  you  try  to  multiply  number  and  string .
  then  javaScript  treated  that string  as to  number

 var str_var =  "5" ;
 var num_var =  6 ;

 var  total =  str_var +  num_var ; //56
 var  multiply =  str_var *  num_var ; //30
      total =  Number(str_var) +  num_var ; //11

 var num_var = String(num_var);

# var  folat_var  =  3.14156767877 ;
  var  floar_str  =  folat_var.toFixed(5); //3.14156
  document.write((round_num1 <= round_num2) + "<br/>") ;

# var vehicles =  new  Array("car","truck","van") ;
  document.write( vehicles[1] + "<br/>") ;


# for (i  in  vehicles)
   {
     document.write(vehicles[i] + "<br/>") ;
   }

# var  rand_var = (5 < 10) ? "5 is less than 10 ":"5 is greater than 10 " ;
# if (5> 10)
  {
    document.write("5 is  greater than 10" +  "<br/>")
  }
  else if(5<5)
  {
    document.write("5 is  greater than 5" +  "<br/>")
  }
  else
  {
    document.write("5 is less than 5" +  "<br/>")
  }


# var town= "Colombo" ;
  switch(town)
  {
   case "Galle"   :document.write("Town  is  Galle"+  "<br/>") ;break ;
   case "Colombo" :document.write("Town  is  Colombo"+  "<br/>") ;break ;
   default        :document.write("Town  is  not  defined"+  "<br/>") ;break ;
  }


#While  loop
 var count = 1 ;

 while(count <= 10)
 {

    if(count == 6 )
    {
        break ; // 2,4  will  be  print
    }
    if(count % 2 )
    {
        document.write(count + "<br/>") ;
                count ++ ;
    }
    document.write(count + "......"+ "<br/>") ;
                count ++ ;
 }

# //Do while  loop

 var  numThree  =  12 ;
 do
 {
    document.write("Inside Do " + numThree +  "</br>") ;
        numThree -- ;
 }
 while (numThree > 8 );


#  //For  LOop
  for(var num =  0 ; num < 11 ; num ++)
  {
    document.write( num  + "<br/>");
  }

# if  your  browser dont understand  javaScript
 <body>
 <script language="javascript" type ="text/javascript">
  <!---Hide javaScript
   function compare(a,b)
   {
        if(5>10)
    {
        alert("A is less than B");
         }
   }
  -->
</script>
<noscript>
    <h3>This site requires JavaScript</h3>
</noscript>
</body>


#  <script type="text/javascript" src="js/addFunction.js"></script>
   <!--Adding external javascript  file    -->

#  Function  we  dont  have  to  again  again  tasks
   //Created In another .js file
   function addingTwoNumbers(numOnee , numTwoo)
   {
    var  total = numOnee +  numTwoo ;
        return  total ;
   }

#  //Calling  function  from  the  external  javaScript  file.....Begin.....
   document.write( " Sum  of  7 and  9  is ..... = " + addingTwoNumbers(7 , 9 )) ;
 //Calling  function  from  the  external  javaScript  file.....End.......

 

####### Tutorial  Part 2 ######
# In header  tag
<head >
    <style>
          #h3style
        {
            color: gray;
        }
    </style>
</head>

#<body onResize ="changeImage();" onLoad = "alert('website Loaded');">

 <script language = "javascript" type ="text/javascript">
 <!-- Hide JavaScript

    function  changeImage()
        {
        document.getElementById("idImgSucess").style.height = "35%" ;
        document.getElementById("idImgSucess").style.width  = "35%" ;
                return   true ;
    }

    function alertMe()
    {
        alertMsg =  document.idImgSucess.src + "\nHeight: " + document.idImgSucess.height + "\nWidth: "
                            + document.idImgSucess.width ;

        alert(alertMsg) ;
        return  true    ;
        //Has error  of  TypeError: document.idImgSucess is undefined
    }

    function changeColor()
    {
        document.getElementById("h3style").style.color = "red" ;
         document.getElementById("h3style").firstChild.nodeValue = "Excited" ;
         return   true ;
    }

    function changeAgain()
        {
            document.getElementById("h3style").style.color = "gray" ;
            document.getElementById("h3style").firstChild.nodeValue = "Bored" ;
             return   true ;
        }

    function showParagraph()
        {
            document.getElementById("idFirstP").style.visiblity  = (document.formm.firstPara.checked)? "visible" :"hidden" ;
            document.getElementById("idSecondP").style.visiblity = (document.formm.secndPara.checked)?"visible" :"hidden" ;
            document.getElementById("idThirdP").style.visiblity  = (document.formm.thirdPara.checked)? "visible" :"hidden" ;
           
             return   true ;
        }


 -->
</script>
<noscript>
    <h3>This site requires JavaScript</h3>
</noscript>

 <img  src ="sccess.jpeg"  id = "idImgSucess" onClick= "alertMe();" onDblClick="alert('You Double Clicked');" />
 <h3  id = "h3style" onMouseOver = "changeColor();" onMouseOut = "changeAgain();">RollOver </h3>

<p id = "idFirstP">This is  a Paragraph </p>
<p id = "idSecondP">This is a Paragraph </p>
<p id = "idThirdP">This is  a Paragraph </p>

<form name = "formex">
    <input type = "checkbox" name = "firstPara"  onClick ="showParagraph();"/>
    <input type = "checkbox" name = "secndPara"  onClick ="showParagraph();"/>
    <input type = "checkbox" name = "thirdPara"  onClick ="showParagraph();"/>
</form>

<br/>
<br/>

<form name = "formex">
    <input type = "checkbox" name = "firstPara"  onClick ="showParagraph();"/>
    <input type = "checkbox" name = "secndPara"  onClick ="showParagraph();"/>
    <input type = "checkbox" name = "thirdPara"  onClick ="showParagraph();"/>
</form>


<form name = "formTwo">
    <p>Text Input </p>
    <input type = "text" name = "textInput" onBlur = "alert('onBlur Trigger');" onFocus ="alert('onFocus Triggered');"/>
   
</form>

</body>
</html>

####w3
# var person = "John Doe", carName = "Volvo", price = 200;
# var x = "5" + 2 + 3;
  If you put a number in quotes, the rest of the numbers will be treated as strings, and concatenated.
output  will  be 523
 var x = 2 + 3 + "5";
output  will  be 55


#  +=     x += y     x = x + y
   %=     x %= y     x = x % y 
   /=     x /= y     x = x / y


# JavaScript Comparison Operators

==     equal to
===     equal value and equal type
!=     not equal
!==     not equal value or not equal type
>     greater than
<     less than
>=     greater than or equal to
<=     less than or equal to
?     ternary operator


#JavaScript Logical Operators
Operator     Description
&&         logical and
||         logical or
!         logical not

#JavaScript     Type Operators
Operator     Description
typeof         Returns the type of a variable
instanceof     Returns true if an object is an instance of an object type

#JavaScript Bitwise Operators

Bit operators work on 32 bits numbers.
Any numeric operand in the operation is converted into a 32 bit number. The result is converted back to a JavaScript number.
Operator     Description         Example        Same as     Result        Decimal
&         AND             5 & 1            0101 & 0001     0001          1
|         OR             5 | 1            0101 | 0001     0101          5
~         NOT             ~ 5            ~0101     1010            10
^         XOR             5 ^ 1            0101 ^ 0001     0100           4
<<         Zero fill left shift     5 << 1     0101 << 1  1010              10
>>         Signed right shift     5 >> 1     0101 >> 1  0010               2
>>>         Zero fill right shift     5 >>> 1        0101 >>> 1     0010            2




The examples above uses 4 bits unsigned examples. But JavaScript uses 32-bit signed numbers.
Because of this, in JavaScript, ~ 5 will not return 10. It will return -6.
~00000000000000000000000000000101 will return 11111111111111111111111111111010

Bitwise operators are fully described in the JS Bitwise chapter.

#Operand     Operator     Operand
100     +     50


###
JavaScript Operator Precedence Values
Value     Operator     Description     Example
19     ( )     Expression grouping     (3 + 4)
                 
18     .     Member     person.name
18     []     Member     person["name"]
                 
17     ()     Function call     myFunction()
17     new     Create     new Date()
                 
16     ++     Postfix Increment     i++
16     --     Postfix Decrement     i--
                 
15     ++     Prefix Increment     ++i
15     --     Prefix Decrement     --i
15     !     Logical not     !(x==y)
15     typeof     Type     typeof x
                 
14     *     Multiplication     10 * 5
14     /     Division     10 / 5
14     %     Modulo division     10 % 5
14     **     Exponentiation     10 ** 2
                 
13     +     Addition     10 + 5
13     -     Subtraction     10 - 5
                 
12     <<     Shift left     x << 2
12     >>     Shift right     x >> 2
12     >>>     Shift right (unsigned)     x >>> 2
                 
11     <     Less than     x < y
11     <=     Less than or equal     x <= y
11     >     Greater than     x > y
11     >=     Greater than or equal     x >= y
                 
10     ==     Equal     x == y
10     ===     Strict equal     x === y
10     !=     Unequal     x != y
10     !==     Strict unequal     x !== y
                 
6     &&     Logical and     x && y
5     ||     Logical or     x || y
                 
3     =     Assignment     x = y
3     +=     Assignment     x += y
3     -=     Assignment     x -= y
3     *=     Assignment     x *= y
3     %=     Assignment     x %= y
3     <<=     Assignment     x <<= y
3     >>=     Assignment     x >>= y
3     >>>=     Assignment     x >>>= y
3     &=     Assignment     x &= y
3     ^=     Assignment     x ^= y
3     |=     Assignment     x |= y

Pale red entries indicates experimental or proposed technology (ECMASScript 2016 or ES7)

Expressions in parentheses are fully computed before the value is used in the rest of the expression.

## JavaScript Data Types

JavaScript variables can hold many data types: numbers, strings, objects and more:
var length = 16;                               // Number
var lastName = "Johnson";                      // String
var x = {firstName:"John", lastName:"Doe"};    // Object


#JavaScript has dynamic types. This means that the same variable can be used to hold different data types:

var x;               // Now x is undefined
var x = 5;           // Now x is a Number
var x = "John";      // Now x is a String

# Strings are written with quotes. You can use single or double quotes:

#  var y = 123e5;      // 12300000
   var z = 123e-5;     // 0.00123

# Booleans can only have two values: true or false.
    var x = true;
    var y = false;
#JavaScript arrays are written with square brackets.
var cars = ["Saab", "Volvo", "BMW"];

# JavaScript objects are written with curly braces.

Object properties are written as name:value pairs, separated by commas.
var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};

# You can use the JavaScript typeof operator to find the type of a JavaScript variable.
The typeof operator returns the type of a variable or an expression:

typeof ""                  // Returns "string"
typeof "John"              // Returns "string"
typeof "John Doe"          // Returns "string"



#The typeof operator can return one of these primitive types:

    string
    number
    boolean
    null
    undefined


# The typeof operator can return one of two complex types:

    function
    object

Example
typeof [1,2,3,4]             // Returns "object" (not "array", see note below)
typeof {name:'John', age:34} // Returns "object"
typeof function myFunc(){}   // Returns "function"


The typeof operator returns "object" for arrays because in JavaScript arrays are objects.

# Unfortunately, in JavaScript, the data type of null is an object.
  You can empty an object by setting it to null:
  var person = null;         // Value is null, but type is still an object



#Difference Between Undefined and Null
typeof undefined           // undefined
typeof null                // object
null === undefined         // false
null == undefined          // true




#Objects are variables too. But objects can contain many values.

This code assigns many values (Fiat, 500, white) to a variable named car:
var car = {type:"Fiat", model:"500", color:"white"};


# <script>
  var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};
  document.getElementById("demo").innerHTML =
  person.firstName + " is " + person.age + " years old.";

 </script>



#HTML form validation can be performed automatically by the browser:

If a form field (fname) is empty, the required attribute prevents this form from being submitted:

<form action="/action_page_post.php" method="post">
  <input type="text" name="fname" required>
  <input type="submit" value="Submit">
</form>

##
Validation can be defined by many different methods, and deployed in many different ways.
Server side validation is performed by a web server, after input has been sent to the server.
Client side validation is performed by a web browser, before input is sent to a web server.

#HTML5 introduced a new HTML validation concept called constraint validation.

HTML constraint validation is based on:

    Constraint validation HTML Input Attributes
    Constraint validation CSS Pseudo Selectors
    Constraint validation DOM Properties and Methods

#Constraint Validation HTML Input Attributes
Attribute     Description
disabled     Specifies that the input element should be disabled
max         Specifies the maximum value of an input element
min         Specifies the minimum value of an input element
pattern     Specifies the value pattern of an input element
required     Specifies that the input field requires an element
type          Specifies the type of an input element


#The typeof operator can return one of these primitive types:

    string
    number
    boolean
    null
    undefined
typeof "John"              // Returns "string"
typeof 3.14                // Returns "number"
typeof true                // Returns "boolean"
typeof false               // Returns "boolean"

#The typeof operator can return one of two complex types:

    function
    object
typeof [1,2,3,4]             // Returns "object" (not "array", see note below)
typeof {name:'John', age:34} // Returns "object"
typeof function myFunc(){}   // Returns "function"

The typeof operator returns "object" for arrays because in JavaScript arrays are objects.

# var person;                // Value is undefined, type is undefined

#Why Functions?
You can reuse code: Define the code once, and use it many times.
You can use the same code many times with different arguments, to produce different results.

    function toCelsius(fahrenheit) {
        return (5/9) *  (fahrenheit-32);
    }
    document.getElementById("demo").innerHTML = toCelsius(77);


#In real life, a car is an object.
A car has properties like weight and color, and methods like start and stop:

All cars have the same properties, but the property values differ from car to car.
All cars have the same methods, but the methods are performed at different times.

#Objects are variables too. But objects can contain many values.

This code assigns many values (Fiat, 500, white) to a variable named car:
var car = {type:"Fiat", model:"500", color:"white"};

#Methods are actions that can be performed on objects.
Methods are stored in properties as function definitions.


#<p id="demo"></p>

<script>
var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};
document.getElementById("demo").innerHTML = person.firstName + " is " + person.age + " years old.";
</script>


#You can access object properties in two ways:
objectName.propertyName
or
objectName["propertyName"]


# objectName.methodName()


#Do Not Declare Strings, Numbers, and Booleans as Objects!

When a JavaScript variable is declared with the keyword "new", the variable is created as an object:
var x = new String();        // Declares x as a String object
var y = new Number();        // Declares y as a Number object
var z = new Boolean();       // Declares z as a Boolean object

Avoid String, Number, and Boolean objects. They complicate your code and slow down execution speed.


#In JavaScript, objects and functions are also variables.
 In JavaScript, scope is the set of variables, objects, and functions you have access to.
 JavaScript has function scope: The scope changes inside functions.

# Local variables are created when a function starts, and deleted when the function is completed.

# A variable declared outside a function, becomes GLOBAL.
A global variable has global scope: All scripts and functions on a web page can access it.


#If you assign a value to a variable that has not been declared, it will automatically become a GLOBAL variable.

This code example will declare a global variable carName, even if the value is assigned inside a function.

#