function popup(w,h,site) {
       x = screen.availWidth/2-w/2;
        y = screen.availHeight/2-h/2;
  var popupWindow = window.open(site,'impress','width='+w+',height='+h+',left='+x+',top='+y+',screenX='+x+',screenY='+y+',scrollbars=yes'); 
  
   
	   
	

        popupWindow.focus();
      }