Background blur with -webkit-filter:blur()

[nikem]

I want an Vista/7-aero-glass-style effect on a popup on my site, and it needs to be dynamic. I'm fine with this not being a cross-browser effect as long as the site still works on all modern browsers.My first attempt was to use something like\[code\]#dialog_base{ background:white; background:rgba(255,255,255,0.8); filter:blur(4px); -o-filter:blur(4px); -ms-filter:blur(4px); -moz-filter:blur(4px); -webkit-filter:blur(4px);}\[/code\]However, as I should have expected, this resulted in the content of the dialog being blurred and the background staying clear. Is there any way to use CSS to blur the background of a semitransparent element instead of its contents?