var _zindex = 50;

function initPage()
{
	var _blocks = document.getElementsByTagName("div")
	for (var i=0; i<_blocks.length; i++){
		if(_blocks[i].className.indexOf("block") != -1){
			_blocks[i].style.zIndex = _zindex;
			_zindex = _zindex - 1;
		}
	}
}
if (window.addEventListener)
	window.addEventListener("load", initPage, false);
else if (window.attachEvent)
	window.attachEvent("onload", initPage);