Determine which layer is on the front using JS

I'm trying to change z-index of table cell using JS to bring it on top. Z-index only works when CSS 'position' is set to smth different than normal. The problem is that setting 'position: relative' and z-index for does not work in opera.

So, i'm looking for a way to determine, whether was brought to the front or not withou开发者_开发问答t using z-index. Maybe some DOM attribute? Or maybe someone knows the way to determine position:relative browser capability or smth.

Thanks

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opacity other than 1 changes element's stacking context. opacity:0.9999 might do the trick.