//OnKeyPress="formatar(this, '#####-###')"
function formatar(src, mask)
{
  var i = src.value.length;
  var saida = mask.substring(0,1);
  var texto = mask.substring(i)
if (texto.substring(0,1) != saida)
  {
        src.value += texto.substring(0,1);
  }
}