Introduction to jQuery

So you know html , css and javascript , Now lets know what is jQuery?. jQuery is a cross-platform , open source , client side javascript library. Its was Created by John Resig in 2005 an released in 2006 .

jQuery logo

Why to Use jQuery?

  • It Simplifies the interaction between html and javascript.
  • It can be used to handle events purely in JavaScript. So, the HTML tags and JavaScript can be completely separated.
  • The JavaScript engines of different browsers differ slightly, so JavaScript code that works for one browser may not work on the other. It handles all these cross-browser inconsistencies and provides a consistent interface that works across different browsers.
  • Offers DOM manipulation based on CSS selectors.
  • Has Tons of Plugins.

Usage Examples

First you need to include the jQuery file which is a single javascript file , you can use the CDN hosted file or download the file and include


<script src="jquery.js"></script>


<script src="code.jquery.com/jquery-1.11.1.min.js"></script>

‘$’ is a jQuery alias which is used . If there are other libraries you can use ‘.noConflict()’ mode which relinquishes control of $.The syntax goes like this $(selector).action().


<script>
   $(document).ready(function(){
        $('p').click ( function() { 
              $(this).css('color','blue');
        });
});
</script>     

The above code will change text color of paragraph tag to blue on click.’this’ is a special keyword that is used in methods to refer to the object on which a method is being invoked.

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