function isNum( caractere )
{
  var strValidos = " ()-0123456789"
  if ( strValidos.indexOf( caractere ) == -1 )
	return false;
  return true;
}

function validaTecla(campo, event)
{
	var BACKSPACE =  8;
	var key;
	var tecla;

	CheckTAB = true;
	if (navigator.appName.indexOf("Netscape") != -1)
		tecla = event.which;
	else
		tecla = event.keyCode;

	key = String.fromCharCode( tecla);

	if ( tecla == 13 )
		{document.pesquisa.submit();
		return true;}
	if ( tecla == BACKSPACE )
		return true;
	return ( isNum(key));
}