If an HTML form has two <input type="submit"> buttons, how do I know which got clicked?

Question

Suppose I have the following HTML form:

<form> ... <input type="submit" name="queue" value="Queue item"> <input type="submit" name="submit" value="Submit item"> </form> 

How do I know which button the user clicked (without using javascript)?

I looked at submitted data and it seems that when "Queue Item" is clicked then "queue" = "Queue Item" gets sent to the server. And when "Submit item" is clicked then "submit" = "Submit item" sets sent.

Can I rely on this behavior? Is it documented somewhere in the standard on HTML forms? How do you guys do it?

Answer 1

Yes, you can rely on this; it's fully documented here. The specific relevant lines say:

When a form is submitted for processing, some controls have their name paired with their current value and these pairs are submitted with the form. Those controls for which name/value pairs are submitted are called successful controls.

and

If a form contains more than one submit button, only the activated submit button is successful.