function openWin(url,winWidth,winHeight) {
  var winTop=(screen.height/2)-(winHeight/2);
  var winLeft=(screen.width/2)-(winWidth/2);
  var features='height='+winHeight+',width='+winWidth+',top='+winTop+',left='+winLeft;
  popWin=window.open(url,'',features);
}