var myWindow = new Object();

function clicker(obj) {
  var winname = obj.target;
  if( (myWindow[winname] == null) || (myWindow[winname].closed == true) ) {
      myWindow[winname] =
        window.open(obj.href, obj.target, "scrollbars,resizable,width=400,height=200" );
  }
  window.open(obj.href, obj.target);
  myWindow[winname].focus();

}