function popUp(url,wnd_name,width,height){
	if (top[wnd_name]!=null && typeof(top[wnd_name])=='object' && !top[wnd_name].closed) {
		if(top[wnd_name].document.location.href!=url) top[wnd_name].document.location.href=url;
		top[wnd_name].focus();
	} else {
		top[wnd_name]=window.open(url,wnd_name,'width='+width+',height='+height+',status=no,menubar=no,resizable=no,scrollbars=no,left='+String((screen.width-width)/2)+',top='+String((screen.height-height)/2));
	}
}