function esDigito(sChr){
	var sCod = sChr.charCodeAt(0);
	return ((sCod > 47) && (sCod < 58));
}
function valSep(oTxt){
	var bOk = false;
	bOk = bOk || ((oTxt.value.charAt(2) == "-") && (oTxt.value.charAt(5) == "-"));
	bOk = bOk || ((oTxt.value.charAt(2) == "/") && (oTxt.value.charAt(5) == "/"));
	return bOk;
}
function finMes(oTxt){
	var nMes = parseInt(oTxt.value.substr(3, 2), 10);
	var nRes = 0;
	switch (nMes){
		case 1: nRes = 31; break;
		case 2: nRes = 29; break;
		case 3: nRes = 31; break;
		case 4: nRes = 30; break;
		case 5: nRes = 31; break;
		case 6: nRes = 30; break;
		case 7: nRes = 31; break;
		case 8: nRes = 31; break;
		case 9: nRes = 30; break;
		case 10: nRes = 31; break;
		case 11: nRes = 30; break;
		case 12: nRes = 31; break;
	}
	return nRes;
}
function valDia(oTxt){
	var bOk = false;
	var nDia = parseInt(oTxt.value.substr(0, 2), 10);
	bOk = bOk || ((nDia >= 1) && (nDia <= finMes(oTxt)));
	return bOk;
}
function valMes(oTxt){
	var bOk = false;
	var nMes = parseInt(oTxt.value.substr(3, 2), 10);
	bOk = bOk || ((nMes >= 1) && (nMes <= 12));
	return bOk;
}
function valAno(oTxt){
	var bOk = true;
	var nAno = oTxt.value.substr(6);
	bOk = bOk && ((nAno.length == 2) || (nAno.length == 4));
	if (bOk){
		for (var i = 0; i < nAno.length; i++){
			bOk = bOk && esDigito(nAno.charAt(i));
		}
	}
	return bOk;
}
function valFecha(oTxt){
	var bOk = true;
	
	if (oTxt.value != ""){
		bOk = bOk && (valAno(oTxt));
		bOk = bOk && (valMes(oTxt));
		bOk = bOk && (valDia(oTxt));
		bOk = bOk && (valSep(oTxt));
	}
	return bOK;
}
function validarEmail(valor) {
  if (valor.value != '') {
	  if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(valor.value)){
	  } else {
	   alert("La dirección de email es incorrecta.");
	   valor.value = '';
	   valor.focus();
	  }
  }
 }