function chkEmail(obj, sAlert) {
	if (obj.value != '') { 
		var emailPat=/^(.+)@([\w\d\.\_\-]+)\.([\w\d]{2,4})$/; 
		var matchArray=obj.value.match(emailPat); 
		if (matchArray==null) { alert(sAlert); obj.focus(); return false; }
	}
	else { alert(sAlert); obj.focus(); return false; }
	return true;
}

function check_contatti() {
	if (document.contatti.nome.value == "") { document.contatti.nome.focus(); alert("You must specify your name and last name!"); return (false); }
	if (document.contatti.email.value == "") { document.contatti.email.focus(); alert("You must provide your e-mail!"); return (false); }
	if (chkEmail(document.contatti.email, 'The email address is not valid!')) { }  else { return false; }
	if (document.contatti.richiesta.value == "") { document.contatti.richiesta.focus(); alert("You specify a request!"); return (false); }
}