How to use jQuery to modify the content of HTML tags

With the continuous development of Internet technology, web development has become an indispensable part of people's daily work. As a well-known JavaScript library in web development, jQuery has become an indispensable tool for web developers. Among them, jQuery also has a powerful and easy-to-use operation method for modifying the content of HTML tags. This article will introduce in detail how to use jQuery to modify the content of HTML tags, hoping to help web developers operate web pages more easily.

1. Basic concepts of jQuery

Before introducing how to use jQuery to modify the content of HTML tags, we need to understand some basic concepts first.

jQuery is a lightweight JavaScript library. Its main function is to encapsulate some common operations of JavaScript, making the code written in JavaScript more concise, easy to read, and easy to maintain. The emergence of jQuery has greatly promoted the development of web development and is currently one of the most popular JavaScript libraries.

To use jQuery to modify the content of HTML tags, you need to be familiar with jQuery's selectors and operation methods.

2. jQuery's selector

Before using jQuery to modify the content of HTML tags, you need to use a selector to select the corresponding HTML tag.

jQuery's selector uses the same syntax as CSS, and can select HTML tags based on attributes such as tag name, class name, ID, etc. The following are some commonly used selectors:

1. Tag selector

Use the tag name to select HTML tags, for example:

$('p')  // 选中页面中的所有<p>标签

2. Class The selector

uses the class name to select the HTML tag, for example:

$('.box')  // 选中页面中所有类名为“box”的HTML标签

3. ID selector

uses the ID to select the HTML tag, For example:

$('#header')  // 选中页面中ID为“header”的HTML标签

4. Attribute selector

Select the corresponding HTML tag according to the attributes of the HTML tag, for example:

$('a[href="http://www.google.com"]')  // 选中页面中链接到Google的所有<a>标签

3. jQuery modifies HTML Content of tag

Using jQuery to modify the content of HTML tag, you need to use three methods: .text(), .html() and .val(). Their specific usage is as follows:

1. .text() method

is used to set or return the text content of HTML tags. For example:

$('p').text('Hello world!');  // 把所有<p>标签的文本内容都改为“Hello world!”

$('p').text();  // 获取第一个<p>标签的文本内容

2. .html() method

is used to set or return the HTML content of the HTML tag. For example:

$('div').html('<p>Hello world!</p>');  // 把所有<div>标签的HTML内容改为"<p>Hello world!</p>"

$('div').html();  // 获取第一个<div>标签的HTML内容

3. .val() method

is used to set or return the value of an HTML form element. For example:

$('input:text').val('Hello world!');  // 把页面中所有文本框的值都改为“Hello world!”

$('input:text').val();  // 获取页面中第一个文本框的值

The above method can also pass a callback function as a parameter, which will return a new value to replace the original value. For example:

$('p').text(function(index, text) {
    return text + ' More text.';
});  // 在所有<p>标签的文本内容之后添加“ More text.”。

4. Summary

As a popular JavaScript library, jQuery has very powerful functions. Using jQuery to manipulate the content of HTML tags can make the code more concise and readable, and also greatly improve the efficiency of web development. I believe that through the introduction of this article, readers have already understood how to use jQuery to modify the content of HTML tags. The next step is to put this knowledge into actual web development!

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