function validate ( form ) {
	if (form.email.value == "") {
		alert( "Please insert your e-mail address." );
		form.email.focus();
		return false ;
	} else if (form.email.value != "") {
		re = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
		if (re.test(form.email.value) == false){
			alert("E-mail address is incorrect!");
			form.email.focus();
			return false;
		}
	}
}