jQuery

jQuery is a JavaScript Library.

jQuery is a lightweight, “write less, do more”, JavaScript library.

The purpose of jQuery is to make it much easier to use JavaScript on your website.

jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code.

jQuery also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.

The jQuery library contains the following features:

  • HTML/DOM manipulation
  • CSS manipulation
  • HTML event methods
  • Effects and animations
  • AJAX
  • Utilities

jQuery Syntax

The jQuery syntax is tailor-made for selecting HTML elements and performing some action on the element(s).

Basic syntax is: $(selector).action()

  • A $ sign to define/access jQuery
  • A (selector) to “query (or find)” HTML elements
  • A jQuery action() to be performed on the element(s)

Examples:

$(this).hide() – hides the current element.

$(“p”).hide() – hides all <p> elements.

$(“.test”).hide() – hides all elements with class=”test”.

$(“#test”).hide() – hides the element with id=”test”.

jQuery – The noConflict() Method

What if you wish to use other frameworks on your pages, while still using jQuery?

jQuery and Other JavaScript Frameworks

As you already know; jQuery uses the $ sign as a shortcut for jQuery.

There are many other popular JavaScript frameworks like: Angular, Backbone, Ember, Knockout, and more.

What if other JavaScript frameworks also use the $ sign as a shortcut?

If two different frameworks are using the same shortcut, one of them might stop working.

The jQuery team have already thought about this, and implemented the noConflict() method.

The jQuery noConflict() Method

The noConflict() method releases the hold on the $ shortcut identifier, so that other scripts can use it.

You can of course still use jQuery, simply by writing the full name instead of the shortcut:

$.noConflict();
jQuery(document).ready(function(){
    jQuery(“button”).click(function(){
        jQuery(“p”).text(“jQuery is still working!”);
    });
});

You can also create your own shortcut very easily. The noConflict() method returns a reference to jQuery, that you can save in a variable, for later use. Here is an example:

var jq = $.noConflict();
jq(document).ready(function(){
    jq(“button”).click(function(){
        jq(“p”).text(“jQuery is still working!”);
    });
});

If you have a block of jQuery code which uses the $ shortcut and you do not want to change it all, you can pass the $ sign in as a parameter to the ready method. This allows you to access jQuery using $, inside this function – outside of it, you will have to use “jQuery”:

$.noConflict();
jQuery(document).ready(function($){
    $(“button”).click(function(){
        $(“p”).text(“jQuery is still working!”);
    });
});

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