function popup(strUrl) {
 
 xPos = 0;
 yPos = 0;
 popupW = 780;
 popupH = 500;
 screenW = screen.width;
 screenH = screen.height;
 
 if(screenW < popupW)
 	popupW = screenW;
 else
 	xPos = (screenW - popupW)/2;
 
 if(screenH < popupH)
 	popupH = screenH;
 else
 	yPos = ((screenH - popupH)/2)-60;
	
	
 winProps = 'width=' + popupW + ',height=' + popupH + ',directories=yes,status=yes,scrollbars=auto,resizable=yes,menubar=yes,toolbar=yes'
 if (navigator.appName.indexOf("Microsoft")>=0)
  winProps+=',left=' + xPos + ',top=' + yPos
 else
  winProps+=',screenX=' + xPos + ',screenY=' + yPos
 
 win = window.open(strUrl,'win',winProps);
}