I have something like:

<input type=textbox id=partNumber onChange=validatePart(this);>

<input type=textbox id=quantity onfocus=saveOldQuantity(this);>

The onChange event is properly firing after a change is made and the textbox loses focus. When quantity gains focus, the onfocus event is properly firing to save the old value of quantity before changes are made.

If validatePart() detects an invalid partNumber value, it alerts the user to that fact. After the alert() has cleared, I'd like to return focus to the partNumber input. But doing a focus() on the input node is not giving it focus. Debugging is tricky here, because the IE debug window interaction is, of course, changing the focus.

How can I ensure focus returns to partNumber if an error is detected in validatePart()?

EDIT:
A simple version of validatePart():

function validatePart(node) {

    if (!node.value) {

        alert('Please enter a part number.');

        node.focus();   // <======= why isn't this having any effect??

    }

}