function validarform() {

if (document.contactform.Nombre.value.length==0 || document.contactform.Apellidos.value.length==0 || document.contactform.Direccion.value.length==0 || document.contactform.Localidad.value.length==0 || document.contactform.CP.value.length==0 || document.contactform.Provincia.value.length==0 || document.contactform.Telefono.value.length==0 || document.contactform.Empresa.value.length==0 || document.contactform.Movil.value.length==0 || document.contactform.EmailFrom.value.length==0 || document.contactform.Medio.value.length==0 || document.contactform.Comentarios.value.length==0 ) {
alert("Por favor complete todos los campos");
return false;
}

document.contactform.submit()
return true;
}