function comprobarCampos(f){
	filtro = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (f.nombre.value.length<3 || f.apellidos.length<3 || !filtro.test(f.correo.value) ){
		window.alert("Check the fields: name,surname and e-mail before submit the form please.");
		return false;
	}
	f.submit();
	return true;
}