A script that will be run asynchronously as soon as it is available:
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:
The numbers in the table specify the first browser version that fully supports the attribute.
Attribute | |||||
---|---|---|---|---|---|
async | Yes | 10.0 | 3.6 | Yes | Yes |
The async attribute is new in HTML5.
In XHTML, attribute minimization is forbidden, and the async attribute must be defined as <script async="async">.