How to modify html using javascript

Javascript is a powerful scripting language that is widely used in web development, especially for modifying content in HTML documents. This article will introduce how to use Javascript to modify HTML.

1. Get HTML elements

Before using Javascript to modify HTML, you first need to obtain the HTML element to be modified. We can use the getElementById() method, getElementsByClassName() method, getElementsByTagName() method and other methods of the document object to obtain HTML elements.

For example, if you want to get the div element with the ID "content":

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

2. Modify the content of the HTML element

With the reference of the HTML element , we can use Javascript to modify the content of HTML. JavaScript provides a variety of methods to modify the content of HTML elements. The following are some common methods:

1. innerHTML attribute

The innerHTML attribute can get or set the content in the HTML element. For example, the following code changes the content of the div element with the ID "content" to "Hello World!":

content.innerHTML = "Hello World!";

2. textContent property

The textContent property can be obtained or set Text content within HTML elements. For example, the following code changes the text content of the div element with the ID "content" to "Hello World!":

content.textContent = "Hello World!";

3. innerText property

TheinnerText property can be obtained by or Sets the text content in the HTML element, but it does not display the HTML markup. For example, the following code changes the text content in the div element with ID "content" to "Hello World!" without displaying the HTML tag:

content.innerText = "Hello World!";

By using the above method, we can easily modify the HTML The content of the document.

3. Add HTML elements

In addition to modifying the content of HTML elements, we can also use Javascript to add HTML elements. HTML elements can be created using the createElement() method of the document object and then inserted into the HTML using the appendChild() or insertBefore() methods.

For example, the following code will create a new p element and then insert it into the div element with the ID "content":

var newParagraph = document.createElement("p");
newParagraph.textContent = "This is a new paragraph.";
content.appendChild(newParagraph);

The above code will insert the new p element into The end of the div element with the ID "content".

If we want to insert a new p element at the beginning of the div element with the ID "content", we can use the insertBefore() method. The following code will create a new p element and insert it at the beginning of the div element with the ID "content":

var newParagraph = document.createElement("p");
newParagraph.textContent = "This is a new paragraph.";
content.insertBefore(newParagraph, content.firstChild);

The above code will insert the new p element into the div with the ID "content" The beginning of the element.

4. Delete HTML elements

Finally, we can also use Javascript to delete HTML elements. HTML elements can be removed from HTML using the removeChild() method.

For example, the following code will delete the first child element from the div element with the ID "content":

content.removeChild(content.firstChild);

The above code will delete the first child element from the div element with the ID "content" a child element.

Summary

In this article, we learned how to use Javascript to modify the content in an HTML document. We can use the getElementById() method, getElementsByClassName() method, getElementsByTagName() method of the document object to obtain the HTML element, use the innerHTML attribute, textContent attribute, innerText attribute and other attributes to modify the content of the HTML element, and use the createElement() method , appendChild() method, insertBefore() method and other methods to add HTML elements, and use removeChild() method to delete HTML elements. Mastering these methods, you can easily modify the content of HTML documents using Javascript.

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