[cYbercOsmOnauT]

I solved it without any phphacking needed and posted it as a template mod. I hope that's okay for you. Also I shortened your javascript.

function Timer() {
	if(x==0) {
		pmBox.bgColor='{ categorybackcolor}";
		x=1;
		return;
	}
		pmBox.bgColor='{ tableheadbgcolor}';
		x=0;
}

Anyways.. very nice idea. Maybe you take my shorter version of your javascript and put it into your version.