var contatti = {
    bind: function(tag, chkName, btnName) {
        var submitName = btnName || 'cmdInvia';
        var btn = $('input[name="'+submitName+'"]');
        var formElem = btn[0].form;
        formElem.action += (formElem.action.indexOf('?') >= 0 ? '&' : '?')
                        + '_ks='
                        + encodeURIComponent(tag);
                        
        if (!chkName)
            return;

        btn.attr('disabled', 'disabled');
        var chkElem = formElem[chkName];
        chkElem.checked = false;
        $(formElem).submit(function() {
            return this[chkName].checked;
        });
        $(formElem[chkName]).click(function() {
            if (this.checked) {
                btn[0].removeAttribute('disabled');
            } else {
                btn[0].setAttribute('disabled', 'disabled');
            }
        });
    }
}