$.validator.addMethod("cap",
    function(value, element) {
        return this.optional(element) || /^\d{5}$/.test(value);
    },
    "Inserire un CAP valido."
);

$.validator.addMethod("codicefiscale",
    function(value, element) {
        return this.optional(element) || /^[A-Za-z]{6}\d{2}[A-Za-z]\d{2}[A-Za-z]\d{3}[A-Za-z]$/.test(value);
    },
    "Inserire un codice fiscale corretto."
);

$.validator.addMethod("data",
    function(value, element) {
        var check = false;
        var re = /^\d{1,2}\/\d{1,2}\/\d{4}$/
        if (re.test(value)) {
            var adata = value.split('/');
            var gg = parseInt(adata[0], 10);
            var mm = parseInt(adata[1], 10);
            var aaaa = parseInt(adata[2], 10);
            var xdata = new Date(aaaa, mm - 1, gg);
            if ((xdata.getFullYear() == aaaa) && (xdata.getMonth() == mm - 1) && (xdata.getDate() == gg)) {
                check = true;
            }
            else {
                check = false;
            }
        }
        else {
            check = false;
        }
        return this.optional(element) || check;
    },
    "Inserire una data valida."
);