self-or-ancestor in one whack?

[Walter Lee Davis]

I use this construction quite a lot:

var elm = evt.element();
if(elm.tagName.toString().toLowerCase() != 'td') elm = elm.up('td');

whenever I am constructing a rollover listener, since it works around
the whole issue with mouseover / out events firing whenever you move
over a child of the element you're trying to observe. Is there a
simpler way to do this, a more Prototype-y way, that is? I've had a
look around the API, and I also had a Google, but the former didn't
turn up anything useful and the latter turned up every commit message
from every project that includes Prototype.

Thanks in advance,

Walter

[ColinFine]

I belive that is what Element.findElement is for.

Colin

[Walter Lee Davis]

I'll give that a try. I'm not sure (from the API docs) if that's going
to do exactly what I want or not.

Thanks,

Walter

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[Tobie Langel]

var elm = evt.findElement('td');

is exactly the same as doing:

var elm = evt.element();
if(elm.tagName.toString().toLowerCase() != 'td') elm = elm.up
('td');

Only it'll accept any kind of CSS selector.

[Matt Foster]

You could use a closure to ensure you're dealing with the right
element.

$$('.my_table td').each(function(cell){

cell.observe('mouseover', listener.curry(cell));

});

function listener(cell, evt){
if(evt.element() != cell)
return false;
}

Are you trying to have a clean way to avoid flickering?

--

http://positionabsolute.net

[Walter Lee Davis]

On Dec 22, 2009, at 12:41 PM, Matt Foster wrote:

> You could use a closure to ensure you're dealing with the right
> element.
>
> $$('.my_table td').each(function(cell){
>
> cell.observe('mouseover', listener.curry(cell));
>
> });
>
> function listener(cell, evt){
> if(evt.element() != cell)
> return false;
> }
>
> Are you trying to have a clean way to avoid flickering?
>

Sort of, really just trying to make sure that mouseover events
triggered by child elements are "credited" to the parent. I tried
Tobie's technique, and it works perfectly. My long-hand method worked
fine as well -- no flickering I could discern -- so it's really just a
coding elegance refinement I was going for rather than anything else.
I am using event delegation -- observing the entire table once rather
than each cell -- so maybe that's why I wasn't seeing any flicker.

Walter