The similarities and differences between innerHTML and outerHTML

Table of Contents

  • 1. innerHTML
  • Two, outerHTML
  • 3. The common points of innerHTML and outerHTML
  • Fourth, the difference between innerHTML and outerHTML

1. innerHTML

In JavaScript, innerHTML is an attribute used to get or set the content of HTML elements. It allows us to dynamically manipulate the content of HTML elements, including text content and nested HTML tags.

Using the innerHTML attribute, we can get the content of an HTML element, for example:

const element = document. getElementById('myElement');
console.log(element.innerHTML);

The above code will print out the HTML content of the myElement element. If the content of the myElement element is

Hello, world!

, then the output will be

Hello, world!

.

In addition to getting HTML content, innerHTML can also be used to set the content of HTML elements. For example, we can dynamically modify the content of an element through the innerHTML attribute:

const element = document. getElementById('myElement');
element.innerHTML = '<p>This is a new paragraph.</p>';

The above code will replace the content of the myElement element with

This is a new paragraph.

.

It should be noted that using the innerHTML attribute to manipulate HTML content may have security risks. Because it can parse and execute arbitrary HTML code, it may lead to the risk of cross-site scripting (XSS). To avoid security issues, handle user input carefully and use other safer methods for manipulating HTML content, such as using the textContent attribute for plain text content.

Summary: The innerHTML attribute is an attribute used in JavaScript to obtain and set the content of HTML elements, which can facilitate dynamic HTML content operations. But you need to pay attention to safety issues when using it.

2. outerHTML

In JavaScript, outerHTML is an attribute used to get or set the complete HTML representation of the HTML element and its contained content. Unlike innerHTML, outerHTML returns the entire HTML code including the element itself.

Using the outerHTML attribute, we can get the complete HTML representation of an HTML element and its content, for example:

const element = document. getElementById('myElement');
console.log(element.outerHTML);

The above code will print out the complete HTML representation of the myElement element and its contained content. If the content of the myElement element is

Hello, world!

, then the output will be

Hello, world!

.

Different from the innerHTML attribute, outerHTML can also be used to replace the entire HTML element and its content. For example, we can dynamically replace elements with the outerHTML attribute:

const element = document. getElementById('myElement');
element.outerHTML = '<div id="newElement"><p>This is a new element.</p></div>';

The above code will replace the myElement element and its content with

This is a new element.

.

It should be noted that, like innerHTML, using the outerHTML attribute also has security risks. Because it can parse and execute arbitrary HTML code, it may lead to the risk of cross-site scripting (XSS). Also, to avoid security issues, user input should be handled with care and other safer methods of manipulating HTML content should be used.

Summary: The outerHTML attribute is an attribute used in JavaScript to obtain and set the complete HTML representation of HTML elements and their contents, and returns the entire HTML code including the element itself. Also need to pay attention to security issues. ,

3. Common features of innerHTML and outerHTML

In JavaScript, innerHTML and outerHTML have the same point, as follows:

  1. Used to get and set HTML content: Either innerHTML or outerHTML can be used to get and set the content of HTML elements.

  2. The target of the operation is the same element: Whether you use innerHTML or outerHTML, you are operating on the same HTML element, but the scope of operation is different .

  3. Support HTML strings as parameters: Whether using innerHTML or outerHTML, you can use HTML strings as parameters when setting HTML content. This makes them very flexible and can dynamically generate or modify the HTML structure.

  4. Both can be used to create new HTML elements: Whether you use innerHTML or outerHTML, you can create new HTML elements by setting HTML strings . For example, you can create a new set of HTML elements by using the innerHTML attribute to set HTML content for an empty div element.

It should be noted that although innerHTML and outerHTML have the same purpose and purpose, they need to be distinguished when using them to ensure correct operation and Manage HTML content.

4. The difference between innerHTML and outerHTML

In JavaScript, innerHTML and outerHTML are two commonly used attributes for manipulating the content of HTML elements. There are some important differences between them, as described below:

  1. The range of content to be obtained or set is different: The innerHTML attribute is used to obtain or set the content inside the HTML element, that is, the child nodes of the element. The outerHTML attribute is used to get or set the complete HTML representation of the HTML element and its content, including the element itself.

  2. The results returned are different: When using the innerHTML attribute to get the element content, what is returned is a string that contains the HTML representation of all child nodes of the element. When using the outerHTML attribute to get the element content, a string is returned, which contains the complete HTML representation of the entire HTML element and its content.

  3. The way to replace an element is different: If we want to replace an element, when using the innerHTML attribute, we need to assign the new HTML code to the innerHTML of the element > Properties. In this way, the child nodes of the element will be replaced with the new HTML code. When using the outerHTML attribute, you need to assign the new HTML code to the outerHTML attribute of the element, which will completely replace the entire HTML element and its content.

  4. Performance difference: Performance-wise, innerHTML is generally more efficient than outerHTML. Because when we use the innerHTML attribute to set the content of an element, only the child nodes of the element will be re-parsed and rendered, and the element itself will not be affected. When using the outerHTML attribute to set the content of an element, the entire element and its content will be re-parsed and rendered, which may cause performance overhead.

It should be noted that whether you use innerHTML or outerHTML, you should pay attention to prevent security risks and avoid executing malicious or untrusted HTML code. User input should be handled with care and other safer methods of manipulating HTML content should be used.

Summary: The innerHTML attribute is used to get or set the content inside the HTML element, and returns the HTML representation of the child node; the outerHTML attribute is used to get or set the HTML element and The full HTML representation of the content it contains returns an HTML representation of the entire HTML element and its content. They also differ in how and performance they replace elements.