function popup(winname, url, winwidth, winheight, scrollbars){

	  // Center the popup window
	  var top   = 0;
	  var left  = 0;

	  var urlPrefix = "";
	  var winurl    = url;

	  //var winname   = "popup";
	  var winopt    = "toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=" + scrollbars + ",copyhistory=0,resizable=0,width="+winwidth+",height="+winheight+",left="+left+",top="+top;
	  newwin    = window.open(winurl,winname,winopt);

	}