Determining the Default Submit Button in HTML Forms

When submitting an HTML form without clicking a specific submit button, such as by pressing Enter or using HTMLFormElement.submit() in JavaScript, browsers need to determine which of multiple submit buttons (if any) should be treated as the one pressed. This determination has implications for triggering onclick event handlers and the data sent to the web server.

Browser Behavior

Experiments have shown that:

• When pressing Enter:

  • Firefox, Opera, and Safari use the first submit button in the form.
  • IE may use either the first submit button or none at all, depending on unspecified conditions.

• When using HTMLFormElement.submit():

  • All browsers use none of the submit buttons.

Standards Specification

The HTML standard does not explicitly specify the behavior for submitting a form without a specific button. It only requires that the form be submitted when a submit button is activated.

Recommended Approach

Given the lack of a clear standard and the variance in browser behavior, it is recommended to avoid relying on a specific default submit button when designing HTML forms. Instead, clearly indicate which submit button should be used in any given scenario.