function wpopup(url,h,w,features,center,n) {
	if (center==1) {
		ytop = Math.floor((screen.height-h)/2);
		ftop = "top="+ytop;
		left = Math.floor((screen.width-w)/2);
		fleft = "left="+left;
	}
	feat="";
	if (ftop || fleft) {
		feat = ftop+","+fleft+",";
	}
	feat += "height="+h+",width="+w;
	feat += (features!="")?(","+features):"";
	window.open(url,(!n)?"newwin":n,feat);
}