Explore the meaning of the $ symbol in jQuery

The

$ symbol plays a very important role in jQuery. It is actually an alias of a function, used to replace the call to the global object jQuery. In jQuery, use the $ symbol instead of the global object jQuery to simplify code writing and improve code readability.

First, let’s take a look at the definition and usage of the $ symbol in jQuery:

// 定义jQuery的别名$
var $ = jQuery;

// 使用$符号来选择元素并对其进行操作
$('#myElement').hide();

// 使用$符号来创建新的元素
var newElement = $('<div>这是一个新的div元素</div>');

In the above code, the $ symbol is used to select elements, operate on elements, and create new Elements. By setting the alias of the global object jQuery to $, you can use various functions of the jQuery library conveniently and quickly.

In addition, the $ symbol can also accept a selector as a parameter to select elements on the page:

// 使用$符号选择所有class为myClass的元素
$('.myClass').css('color', 'red');

// 使用$符号选择所有标签名为div的元素
$('div').addClass('highlight');

In addition to being an alias for functions, the $ symbol also has other functions in jQuery Purpose, for example:

1. Wait for the document to be loaded and execute the code:

$(document).ready(function() {
    // 在文档加载完成后执行的代码
});

2. Processing event listening:

$('#myButton').click(function() {
    // 点击按钮后执行的代码
});

3. Chained operations:

$('#myElement').css('background-color', 'yellow').hide(1000).show(1000);

Multiple operations can be conveniently linked together through the $ symbol, making the code more concise and easier to read.

To sum up, the $ symbol has a very important meaning in jQuery. It is not only an alias of the global object jQuery, but also represents the powerful selector and operation functions of jQuery. Through the $ symbol, we can quickly and easily operate page elements and write elegant and concise code. In actual development, a deep understanding of the meaning and usage of the $ symbol will help improve the efficiency and quality of the code.

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