[javascript] jQuery trigger event when click outside the element

    var visibleNotification = false;

  function open_notification() {
        if (visibleNotification == false) {
            $('.notification-panel').css('visibility', 'visible');
            visibleNotification = true;
        } else {
            $('.notification-panel').css('visibility', 'hidden');
            visibleNotification = false;
        }
    }

    $(document).click(function (evt) {
        var target = evt.target.className;
        if(target!="fa fa-bell-o bell-notification")
        {
            var inside = $(".fa fa-bell-o bell-notification");
            if ($.trim(target) != '') {
                if ($("." + target) != inside) {
                    if (visibleNotification == true) {
                        $('.notification-panel').css('visibility', 'hidden');
                        visibleNotification = false;
                    }
                }
            }
        }
    });