Event bubbling and the onblur event

Question

I'm writing a form validation script and would like to validate a given field when its onblur event fires. I would also like to use event bubbling so i don't have to attach an onblur event to each individual form field. Unfortunately, the onblur event doesn't bubble. Just wondering if anyone knows of an elegant solution that can produce the same effect.

Answer 1

You're going to need to use event capturing (as opposed to bubbling) for standards-compliant browsers and focusout for IE:

if (myForm.addEventListener) {
    // Standards browsers can use event Capturing. NOTE: capturing 
    // is triggered by virtue of setting the last parameter to true
    myForm.addEventListener('blur', validationFunction, true);
}
else {
    // IE can use its proprietary focusout event, which 
    // bubbles in the way you wish blur to:
    myForm.onfocusout = validationFunction;
}

// And of course detect the element that blurred in your handler:
function validationFunction(e) {
    var target = e ? e.target : window.event.srcElement;

    // ...
}

See http://www.quirksmode.org/blog/archives/2008/04/delegating_the.html for the juicy details