function popupcenter(Url,Name,PosFimX,PosFimY,ScrollBars,Resizable)
{
  PosIniX=((screen.availWidth/2)-(PosFimX/2));
  PosIniY=((screen.availHeight/2)-(PosFimY/2));
  window.open(Url,Name,'toolbar=0,location=0,directories=0,menubar=0,status=0,scrollbars='+ScrollBars+',resizable='+Resizable+',top='+PosIniY+',left='+PosIniX+',width='+PosFimX+',height='+PosFimY+'');
};