function openPopUp(theURL,winName,features, myWidth, myHeight, isCenter) {
	if(window.screen)if(isCenter){
		var myLeft = (screen.width-myWidth)/2;
		var myTop = (screen.height-myHeight)/2;
		features+=(features!='')?',':'';
		features+='left='+myLeft+',top='+myTop+'';
	}
	window.open(theURL,winName, features+((features!='')?',':'')+'resizable=yes, scrollbars=yes, width='+myWidth+',height='+myHeight);
}



 function cerrar_popup() {
  var ventana = window.self;
  ventana.opener = window.self;
  ventana.close();
 }