var win = null; 
      function centerWin( url, winName, width, height, scroll ) 
	  { 
        var winl = (screen.width-width) / 2; 
        var wint = (screen.height-height) / 2; 
        var settings ='height='+height+','; 
        settings +='width='+width+','; 
        settings +='top='+wint+','; 
        settings +='left='+winl+',' 
        settings +='scrollbars='+scroll+','; 
        settings +='resizable=yes'; 

        win=window.open( url, winName, settings ); 

        if (parseInt(navigator.appVersion) >= 4) { 
          win.window.focus(); 
       } 
       }