function openWin(ventana,popW,popH){
	var w = 0, h = 0;

   	w = screen.width;
   	h = screen.height;
   	
	var leftPos = (w-popW)/2, topPos = (h-popH)/2;

    popupWindow=open(''+ventana+'','window','resizable=no,scrollbars=yes,width='+popW+',height='+popH+',top='+topPos+',left='+leftPos);
    if (popupWindow.opener == null){popupWindow.opener = self;}
}