function popup(url){
    var winWidth = 800;
    var winHeight = 600;
    var startX = (screen.availWidth - winWidth) / 2;
    var startY = (screen.availHeight - winHeight) / 2;    
    var popup = window.open(url, "popup", "screenX="+startX+",screenY="+startY+",left="+startX+",top="+startY+",height="+winHeight+",width="+winWidth+",directories=no,location=no,menubar=no,resizable=yes,scrollbars=yes,status=no,toolbar=no");
}

function setOpacity(opacity, id) {
	var el = document.getElementById(id).style;
	el.opacity = (opacity / 100);
	el.MozOpacity = (opacity / 100);
	el.KhtmlOpacity = (opacity / 100);
	el.filter = "alpha(opacity=" + opacity + ")";
}