function openwin(page, w, h,winName) {
	sw=screen.availWidth/2-w/2;
	sh=screen.availHeight/2-h/2;
	var new_win=window.open(page,winName,'toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width='+w+',height='+h+',top='+sh+',screenY='+sh+',left='+sw+',screenX'+sw);
	new_win.focus();
}