Script defer Property

Find out if a script was executed when a page was finished parsing:

var x = document.getElementById("myScript").defer

The result of x will be:

true

Definition and Usage

The defer property sets or returns whether a script should be executed when a page has finished parsing, or not.

This property reflects the defer attribute of the <script> tag.

Note: The defer 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

The defer property is supported in all major browsers.

Note: The defer attribute is not supported in Opera 12 and earlier versions.

Return the defer property:

scriptObject.defer

Set the defer property:

scriptObject.defer=true|false

Value	Description
true\|false	Specifies whether a script should be executed when the page has finished parsing, or not true - The script is executed when the page has finished parsing false - The script will not be executed when the page has finished parsing

Return Value:	A Boolean, returns true if the script is executed when the page has finished parsing, otherwise it returns false