Demystifying the Magical Power of the Dollar Sign in jQuery

The magic parsing of $ in jQuery

In front-end development, jQuery is undoubtedly a very popular and powerful JavaScript library. In jQuery, there is a special symbol $, which plays a powerful role as the core identifier of jQuery. This article will deeply analyze the magic of $ in jQuery and demonstrate its power through specific code examples.

1. The definition and role of $

In jQuery, $ is actually an alias of a function, which allows us to call jQuery methods through $(). For example, we can select the element with the id myElement in the following way:

$('#myElement')

$() function plays a very important role in jQuery. It can be used to select elements, create elements, and bind events. , initiate ajax request, etc.

2. Basic usage of $

1. Select elements

We can use the $() function to select elements in the DOM, for example: select all The p element and the element with the class name test:

$('p') //选取所有p元素
$('.test') //选取类名为test的元素

2. Binding events

We can use the $() function to bind events, such as: add for buttons Click event:

$('#btn').click(function(){
  alert('Hello, jQuery!');
});

3. Create element

We can use the $() function to create elements, for example: create a div element and add it to the body:

$('<div>This is a new div element</div>').appendTo('body');

3. Advanced usage of $

1. Chained operation

The return value of the $() function in jQuery is a jQuery object, so chained operations can be implemented . For example, setting the style of an element and binding events can be operated continuously:

$('#myElement').css('color', 'red').click(function(){
  alert('Hello, jQuery!');
});

2. Use $ as the variable name

Although $ is usually an alias for jQuery, we It can also be used as a variable name. For example, we can define a variable like this:

var $myElement = $('#myElement');

So that $myElement can be used directly in the code instead of $('#myElement').

Summary

$, as the identifier of jQuery, plays a very important role in front-end development. Through the analysis and specific code examples of this article, I hope readers will have a deeper understanding of the magic of $ in jQuery. In actual development, making more use of the powerful symbol $ can make our code more concise and elegant.

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