function openCatalog( strURL ){
   var screen_width = 975;
   var screen_height = 720;
   strFeatures = "left=0,top=0,width=" + screen_width + ",height=" + screen_height + ",";
   strFeatures += "toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no";

   windowname=window.open( strURL, "DBookWin", strFeatures );
   windowname.focus();
   return;
   }

var winV = "";
var Vflg = 0;

function zoom(url){ 

  if (Vflg == 1) {
      winV.close();
    }

winV = window.open(url, "window_name", "width=520,height=520,scrollbars=no"); 
//winV = window.open(url, "window_name", "width=600,height=600,scrollbars=no"); 
Vflg = 1;

}