HTML async Attribute - HTML Attribute

Definition and Usage

The async attribute is a boolean attribute.

When present, it specifies that the script will be executed asynchronously as soon as it is available.

Note: The async attribute is only for external scripts (and should only be used if the src attribute is present).

Note: There are several ways an external script can be executed:

If async is present: The script is executed asynchronously with the rest of the page (the script will be executed while the page continues the parsing)
If async is not present and defer is present: The script is executed when the page has finished parsing
If neither async or defer is present: The script is fetched and executed immediately, before the browser continues parsing the page

Applies to

The async attribute can be used on the following element:

Elements	Attribute
<script>	async

Browser Support

The numbers in the table specify the first browser version that fully supports the attribute.

How to add HTML async Attribute in HTML Page

It is A script that will be run asynchronously as soon as it is available.

index.html

Example: HTML

<!DOCTYPE html>
<html>
<body>

<h1>The script async attribute</h1>

<p id="p1">Hello World!</p>
<script src="demo_async.js" async></script>

</body>
</html>

Output should be:

html async attribute

Type:	Develop
Category:	Web Tutorial
Sub Category:	HTML Attribute
Uploaded by:	Admin

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