execute function before submit

Question

how would I execute a JavaScript function on a PHP form before submit but after all text is entered?

let's say I want to make all the text uppercase or something.. would onsubmit execute before the PHP takes over?

• Šime Vidas: Bind a submit handler to the FORM element.
• Barend: "would onsubmit execute before the PHP takes over?" --> That's such a great learning question that it'd be criminal not to turn it around on you (honest). In what order do you think onsubmit and PHP will happen? Why?
• cream: the only time i've ever really seen this used is to create an alert saying "thank you for your submission" or something... which seemed simultaneous, but in retrospect the javascript would have had to execute before the php refreshed the page. thanks! i feel smarter already.
• Barend: Yep, that's correct! The web browser executes the onsubmit handler and when the handler completes, the web browser sends the HTTP request to your web server, which forwards it to PHP. Fun fact: if you return false from your onsubmit handler, the web browser aborts the form submit and never sends the HTTP request.

Answer 1

Yes, onSubmit event will be before PHP. Here is jsFiddle example with jQuery. Of course you can use native event handler or whatever you like. I use that, bacause it is faster :)

Answer 2

Here is a non-jQuery jsfiddle version, that uses the onSubmit handler.