Clicking on a div's scroll bar fires the blur event in I.E

Question

I have a div that acts like a drop-down. So it pops-up when you click a button and it allows you to scroll through this big list. So the div has a vertical scroll bar. The div is supposed to disappear if you click outside of the div, i.e. on blur.

The problem is that when the user clicks on the div's scrollbar, IE wrongly fires the onblur event, whereas Firefox doesn't. I guess Firefox still treats the scrollbar as part of the div, which I think is correct. I just want IE to behave the same way.

Answer 1

I've had a similar problem with a scrollbar in an autocomplete dropdown. Since the dropdown should be hidden when the form element it is attached to loses focus, maintaining focus on the correct element became an issue. When the scrollbar was clicked, only Firefox (10.0) kept focus on the input element. IE (8.0), Opera (11.61), Chrome (17.0) and Safari (5.1) all removed focus from the input, resulting in the dropdown being hidden, and since it was hidden, click events would not fire on the dropdown.

Fortunately, the shift of focus can be easily prevented in most of the problem browsers. This is done by canceling the default browser action:

dropdown.onmousedown = function(event) {
    // Do stuff
    return false;
}

Adding a return value to the event handler sorted out the problem on all browsers except IE. Doing this cancels the default browser action, in this case the focus shift. Also, using mousedown instead of click meant that the event handler would be executed before the blur event fired on the input element.

This left IE as the only remaining problem (no surprise there). It turns out that there is no way to cancel the focus shift on IE. Fortunately, IE is the only browser that fires a focus event on the dropdown, meaning focus on the input element can be restored with an IE-exclusive event handler:

dropdown.onfocus = function() {
    input.focus();
}

This solution for IE is not perfect, but while the focus shift is not cancelable, this is the best you can do. What happens is that the blur event fires on the input, hiding the dropdown, after which focus fires on the now hidden dropdown, which restores focus on the input and triggers showing the dropdown. In my code it also triggers repopulating the dropdown, resulting in a short delay and loss of the selection, but if the user wants to scroll the selection is probably useless anyway, so I deemed this acceptable.

I hope this is helpful, even though my example is slightly different than in the question. From what I gathered, the question was about IE firing a blur event on the dropdown itself, rather than the button that opened it, which makes no sense to me... Like my use of a focus event handler indicates, clicking on a scrollbar should move focus to the element the scrollbar is part of on IE.