function validar_contacto(form) {
	if (form.nombreyapellido.value == '') { alert('You must complete your full name'); form.nombreyapellido.focus(); return false; }
	if (form.email.value.indexOf('@') < 0 || form.email.value.indexOf('.') < 0 || form.email.value.indexOf(',') > 0) { alert('An error exist in email field'); form.email.focus(); return false; }
	if (form.asunto.value == '') { alert('You must complete Subject'); form.asunto.focus(); return false; }
	if (form.mensaje.value == '') { alert('You must complete message'); form.mensaje.focus(); return false; }
	return true;
}