onsubmit Attribute

Where to use the onsubmit Attribute

• As Type Script:
  onsubmit is declared on the element: form

Description

The onsubmit attribute may be used on a form element to specify script to be executed when a Submit button for the form is activated. Note: The onsubmit handler is not invoked if the form is submitted by using the JavaScript method Form.submit().

If the onsubmit script returns false then the form will not be submitted (in script-enabled user agents) so it is useful for form data validation.

See also the onreset and onclick attributes.

If you use this attribute (or any attributes of Type Script) the MIME type of the scripting language used should always be provided in a Content-Script-Type HTTP header.

It is good practice not to use these attributes, however, and instead to include external scripts (via script elements) which add any handlers unobtrusively. This makes code more self-contained and also the XHTML is easier to maintain if it doesn't contain any events attributes.