function PopUp(url, left, top, width, height, toolbar, menubar, statusbar, scrollbar, resizable)
{
  toolbar_str = toolbar ? 'yes' : 'no';
  menubar_str = menubar ? 'yes' : 'no';
  statusbar_str = statusbar ? 'yes' : 'no';
  scrollbar_str = scrollbar ? 'yes' : 'no';
  resizable_str = resizable ? 'yes' : 'no';
  d = new Date();
  ventana = window.open(url, 'nueva'+d.getTime(), 'left='+left+',top='+top+',width='+width+',height='+height+',toolbar='+toolbar_str+',menubar='+menubar_str+',status='+statusbar_str+',scrollbars='+scrollbar_str+',resizable='+resizable_str);
  ventana.focus();
}

function PopUpCentrado(url, width, height, scrollbar)
{
	var left = screen.width/2 - width/2;
	var top = screen.height/2 - height/2;
	PopUp(url, left, top, width, height,0,0,0,scrollbar,0);
}