问jQuery在自定义插件上实现销毁方法

EN

// BEGIN THE PLUGIN
var globalContainer;
(function($) {

$.fn.upCount = function(options, callback) {
    var settings = $.extend({
        startTime: null,
        offset: null,
        reset: null,
        resume: null
    }, options);

    // Save container
    var container = this;
    globalContainer = container.parent().html();

    // get the current date
    var currentDate = function() {
        // get client's current date
        var date = new Date();

        // turn date to utc
        var utc = date.getTime() + (date.getTimezoneOffset() * 60000);

        // set new Date object
        var new_date = new Date(utc + (3600000 * settings.offset))

        return new_date;
    };

    // Define some global vars
    var original_date = currentDate();
    var target_date = new Date('12/31/2020 12:00:00'); // Count up to this date

    // Are we resetting our counter?
    if(settings.reset){
        reset();
    }

    // Do we need to start our counter at a certain time if we left and came back?
    if(settings.startTime){
        resumeTimer(new Date(settings.startTime));
    }

    // Reset the counter by destroying the element it was bound to
    function reset() {
        var timerContainer = $('[name=timerContainer]');
        timerContainer.empty().append(globalContainer).find('.time').empty().append('00');
    }

    // Given a start time, lets set the timer
    function resumeTimer(startTime){
       original_date = startTime;
    }

    // Start the counter
    function countUp() {

        // Set our current date
        var current_date = currentDate(); 

        // difference of dates
        var difference = current_date - original_date;
        //console.log(original_date)

        if (current_date >= target_date) {
            // stop timer
            clearInterval(interval);
            if (callback && typeof callback === 'function') callback();
            return;
        }

        // basic math variables
        var _second = 1000,
            _minute = _second * 60,
            _hour = _minute * 60,
            _day = _hour * 24;

        // calculate dates
        var days = Math.floor(difference / _day),
            hours = Math.floor((difference % _day) / _hour),
            minutes = Math.floor((difference % _hour) / _minute),
            seconds = Math.floor((difference % _minute) / _second);

        // fix dates so that it will show two digets
        days = (String(days).length >= 2) ? days : '0' + days;
        hours = (String(hours).length >= 2) ? hours : '0' + hours;
        minutes = (String(minutes).length >= 2) ? minutes : '0' + minutes;
        seconds = (String(seconds).length >= 2) ? seconds : '0' + seconds;

        // based on the date change the refrence wording
        var ref_days = (days === 1) ? 'day' : 'days',
            ref_hours = (hours === 1) ? 'hour' : 'hours',
            ref_minutes = (minutes === 1) ? 'minute' : 'minutes',
            ref_seconds = (seconds === 1) ? 'second' : 'seconds';

        // set to DOM
        container.find('.days').text(days);
        container.find('.hours').text(hours);
        container.find('.minutes').text(minutes);
        container.find('.seconds').text(seconds);

        container.find('.days_ref').text(ref_days);
        container.find('.hours_ref').text(ref_hours);
        container.find('.minutes_ref').text(ref_minutes);
        container.find('.seconds_ref').text(ref_seconds);

        // Update our title
        document.title = 'Task Tracker - ' + days +'.'+hours+':'+minutes+':'+seconds;
    };

    // start
    interval = setInterval(countUp, 1000);
};

})(jQuery);
 // END THE PLUGIN