How to operate html tags with javascript

JavaScript is a client-side scripting language that can be used to operate Html tags in web pages to achieve dynamic effects and user interaction.

The first thing to emphasize is that JavaScript does not directly operate the created HTML tags, but obtains a reference to the specified tag, and then uses the properties and methods in JavaScript to modify and control the tag.

First, we need to get the reference of the specified tag. Commonly used methods include the following:

1. Use the id attribute
   Define the id attribute in the HTML tag, and use the document.getElementById() method in JavaScript to obtain a reference to the tag. For example:

HTML code

<div id="myDiv">这是一个Div标签</div>

JavaScript code

var myDiv = document.getElementById("myDiv");

2. Use class attribute
   Define the class attribute in the HTML tag and in JavaScript Use the document.getElementsByClassName() method to obtain references to all tags of this class. For example:

HTML code

<div class="myClass">这是一个class为myClass的Div标签</div>
<div class="myClass">这是另一个class为myClass的Div标签</div>

JavaScript code

var myDivs = document.getElementsByClassName("myClass");

3. Use tag name
   Use document.getElementsByTagName() method in JavaScript to obtain the specified A reference to all tags with the tag name. For example:

HTML code

<div>这是一个Div标签</div>
<p>这是一个P标签</p>

JavaScript code

var divs = document.getElementsByTagName("div");//获取所有的div标签
var p = document.getElementsByTagName("p");//获取所有的p标签

4. Use querySelector() method
   Use document.querySelector() method in JavaScript Gets a reference to the first matching tag for the specified selector. For example:

HTML code

这是一个class为myClass的Div标签
<div id="myDiv">这是一个Div标签</div>

JavaScript code

var myDiv = document.querySelector("#myDiv");//获取id为myDiv的标签
var myClass = document.querySelector(".myClass");//获取class为myClass的第一个标签

After obtaining the reference of the specified tag, you can use the properties and methods in JavaScript to operate the Html tag . Commonly used operations are as follows:

1. Modify the content and attributes of the tag
   You can use the innerHTML attribute and setAttribute() method of the tag to modify the content and attributes of the tag. For example:

JavaScript code

myDiv.innerHTML = "我是新内容";//修改myDiv的内容为"我是新内容"
myDiv.setAttribute("class", "newClass");//将myDiv的class属性改成"newClass"

2. Showing or hiding tags
   You can use the style.display attribute of the tag to control the display or hiding of the tag. For example:

JavaScript code

myDiv.style.display = "none";//将myDiv标签隐藏

3. Add or delete tags
   You can use the createElement() method to create a new tag, and use the appendChild() method to add a new tag Go to the specified tag and use the removeChild() method to remove the specified tag from the parent element. For example:

JavaScript code

var newDiv = document.createElement("div");//创建新的div标签
newDiv.innerHTML = "我是新添加的div";//设置新标签的内容
myDiv.appendChild(newDiv);//将新标签添加到myDiv中
myDiv.parentNode.removeChild(myDiv);//将myDiv从它的父标签中删除

In summary, by obtaining the reference of the specified tag, you can operate the Html tag in JavaScript to achieve dynamic effects and interactive functions of the web page. Of course, this is just the tip of the iceberg in how JavaScript operates Html tags. There are still many powerful techniques waiting for us to explore and practice.

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