jQuery Events Part - I : Document loading Events and Keyboard Events

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jQuery events

jQuery basically have following type of events:


.ready()

Indicates that DOM is fully loaded that mean all controls and it's hierarchy is fully loaded .This is the best place to do all event handling and jacascript/jQuery code manipulations.

Below example shows how to use .ready() in jQuery:


$(document).ready(function()
{  
  // Handler for .ready() called.
});


.load()
.load event executes code when page is rendered or a perticular element is rendered. Use this event when code is relies on loaded assests like images.

Below example show .load() in jQuery, and this triggers event when page is fully loaded with all control:


$(window).load(function()
{ 
 // Add code here
);

You may call .load for perticular element when it loads.


<img src="something.png" id="imageDemo"/>




$("#imageDemo").load()(function(){
  // Add code here.
});


.unload()
Use this event when user navigates away from the page or window.
Below example shows how .unload() works in jQuery:

$(window).unload(function(){
alert('I am unloading.');
});


.keydown()

Event on element get triggered when user presses any key on keyboard. If you want keydown event get fired when user start typing in some text box.

Below example shows how .keydown() works in jQuery:
For textbox you can write it like


<input id="keyDownDemo" type="text" value="Hello"/>



$("#keyDownDemo").keydown(function(){ 
alert(Hello jQuery KeyDown Happened.');
});

jQuery basics

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Basics of jQuery

In this post we will see very basic of jQuery.How to start with jQuery?jQuery, is a Javascript library with cross-browser support and open source which simplify the client side scripting in web/html.
It supports

  • DOM,
  • CSS manipulation,
  • Ajax,
  • animations and effect
  • extendible plugins.


Get Started using jQuery:
jQuery needs to add library in html or web page which is a .js file that contains Ajax funcions, effects, DOM, events ...etc. You can download jQuery library from http://docs.jquery.com/Downloading_jQuery

After downloading jQuery library add it to page like below:
Sample to start with jQuery:

<!DOCTYPE html >
< html>
<head>
<title>jQuery Demo</title>
<script type="text/javascript" src="jquery.js"></script>
</head>
<body>
<form id="Form1" method="post" runat="server">
</form>
</body>
</html>