Run JavaScript code on form submission

I wa开发者_StackOverflow社区nt to run a JavaScript code upon a form being submitted preceding other default tasks that are carried out on form submit.

Can anyone suggest some approaches?

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For example, here is how you can execute some JS on Drupal's contact form before it is submitted using jQuery:

$('form#contact-mail-page input#edit-submit').click(function() { alert('do some stuff'); });

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I am not sure if drupal has any special way to automate this or make it easier but in just normal HTML javascript you would do it like:

<input type="submit" onClick="doStuff();" value="Submit">  //Note: you can use return(doStuff()); and if doStuff returns false then the form will not submit (great for checking if all fields are filled out correctly).

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you can use this property of

'#attributes' => array('onclick' => 'if(confirm('.$msg.')) return true; return false;'));