function dailog_win(url,windowname,width,height) {
	var features="location=no, menubar=no, status=no, scrollbars=yes, resizable=yes, toolbar=no";
	if (width) {
		if (window.screen.width > width) {
   			features+=", left="+(window.screen.width-width)/2;
		}else{
			width=window.screen.width;
		}
  	features+=", width="+width;
 }
 if (height) {
  	if (window.screen.height > height){
		   features+=", top="+(window.screen.height-height)/2;
		}else{
				height=window.screen.height;
		}
  	features+=", height="+height;
 }
 window.open(url,windowname,features);
}