function check_form() {
	var re_email = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+\.[a-z0-9-]+(\.[a-z0-9-]+)*$/;
	if(re_email.test(f1.email_ami.value)) {
		f1.submit();
	}
	else {
		alert('L\'email de votre ami(e) est incorrecte.');
	}
}