var popUpWin = 0;
function popup(url, width, height, bars, uleft, utop) {
	var left, top;

  if(popUpWin)
  {
    if(!popUpWin.closed) popUpWin.close();
  }

  if(!isNumber(uleft)){
		left = (screen.width/2) - width/2;
	} else {
		left = uleft;
	}

  if(!isNumber(utop)){
		top = (screen.height/2) - height/2;
	} else {
		top = utop;
	}

	agent = navigator.userAgent;
	windowName = 'popUpWin';
	params  = '';
	params += 'toolbar='+ bars +',';
	params += 'location=0,';
	params += 'directories=0,';
	params += 'status=0,';
	params += 'menubar='+ bars +',';
	params += 'scrollbars=1,';
	params += 'resizable=0,';
	params += 'width='+ width +',';
	params += 'height='+ height +',';
	params += 'left='+ left +',';
	params += 'top='+ top;
	popUpWin = window.open(url, windowName , params);
	if (!popUpWin.opener) {
		popUpWin.opener = window;
	}

	function isNumber(inputString)
	{
		return (!isNaN(parseInt(inputString))) ? true : false;
	}
}