How to modify html content with js

JavaScript is a widely used programming language that can be used to modify HTML content, change CSS styles, add dynamic effects, process user input, etc. This article will focus on how to use JavaScript to modify HTML content.

1. DOM operation

In DOM (Document Object Model), each HTML element is treated as an object. Therefore, we can access and modify the attributes of HTML tags through JavaScript.

1. Get the element

We can use the document.getElementById() method to get the element with the specified id, as shown below:

var myElement = document.getElementById("myId");

Similarly, We can also get the element with the specified tag name through the getElementsByTagName() method, as shown below:

var myElements = document.getElementsByTagName("p");

2. Modify the element content

After getting the element, we can use the innerHTML attribute Modify the content of the element. As shown below:

myElement.innerHTML = "新的内容";

Using the innerHTML attribute can make simple text content modifications. If you need to modify the attributes of the element itself, such as id or class, etc., you need to use the JavaScript setAttribute() method.

3. Create new elements

We can use the document.createElement() method to create a new HTML element, as shown below:

var newElement = document.createElement("p");

The above code A new p tag has been created, but the tag has not yet been added to the web page. We need to add elements through the appendChild() method.

4. Insert element

We can use the appendChild() method to insert the newly created element into the specified HTML element, or we can use the insertBefore() method to insert the element to the designated location. As shown below:

document.body.appendChild(newElement);   //将newElement添加到body元素中
document.body.insertBefore(newElement, nextSibling);   //将newElement插入到nextSibling元素之前

2. jQuery library operation

In addition to DOM operations, we can also use the jQuery library to modify HTML content. The jQuery library is a library specifically designed to simplify JavaScript, using it to operate HTML elements faster and more conveniently.

1. Get the element

We can get the specified HTML element through the jQuery selector, as shown below:

var myElement = $("#myId");

2. Modify the element content

Similar to DOM operations, we can also modify the content of elements through the html() method, as shown below:

myElement.html("新的内容");

3. Create new elements

We can use the $() method to create new HTML elements as follows:

var newElement = $("<p></p>");

4. Insert element

Similarly, we can use append( ) and before() methods insert the newly created element into the specified HTML element, as shown below:

$("body").append(newElement);   //将newElement添加到body元素中
myElement.before(newElement);   //将newElement插入到myElement之前

3. Summary

This article mainly introduces how JavaScript operates HTML content. Through the introduction of this article, readers can master the following contents:

• Understand DOM (Document Object Model) operations and master the methods of obtaining, modifying, creating and inserting elements;
• Understand the jQuery library Operation, use methods such as selectors, html(), $(), append() and before() to operate HTML elements;
• Master the basic knowledge of JavaScript to operate HTML and lay the foundation for subsequent development and practice.

Finally, readers need to practice more. Only through personal practice can they better master the method of using JavaScript to operate HTML.

The above is the detailed content of How to modify html content with js. For more information, please follow other related articles on the PHP Chinese website!