for in loop无法按预期运行javascript

Question

I have an object, Object { 2014-01-30=[1], 2014-02-01=[1]}

and an array called fechasPeriodo,

so why is the following code:

fechasPeriodo = [];
            for(var property in SelectedDates) {
            fechasPeriodo.push(new Date(property));
            }

producing this result [Date {Wed Jan 29 2014 18:00:00 GMT-0600}, Date {Fri Jan 31 2014 18:00:00 GMT-0600}]

Edit: I'd expect the result to be Thu Jan 30 2014 etc. , Sun 02 Feb 2014.

Actually it's a problem only because I'm trying to define a range of dates in datepicker using a Google Calendar feed. So the following code:

if(fechasPeriodo.length > 1) {
            r[1] = fechasPeriodo[0] <= date && date <= fechasPeriodo[1] ?"Highlighted"+SelectedDates[key][0].replace(/\s/g, "_"):"Highlighted-unknown";
            }

I'd expect to highlight a range from the 30th Jan to the 02nd of February. But if you can guide me as to why it isn't working, I'd be very grateful, I'm following this fiddle: http://jsfiddle.net/qaEuj/

At the risk of being downvoted again I have to say that I still don't understand why my last bit of code above isn't working like the fiddle I mention, so here's my complete code:

    $(document).ready(function() {
    var fechaDefecto = new Date('2014/01/01');
    var fechaFin = new Date('2014/08/31');
    SelectedDates = null;

    /*SelectedDates[new Date('12/25/2014')] = new Date('12/25/2014');
    SelectedDates[new Date('12/12/2014')] = new Date('12/12/2014');
    SelectedDates[new Date('06/06/2014')] = new Date('06/06/2014');*/
    $('#tiposFechas').change(function() {
    $.getJSON("https://www.google.com/calendar/feeds/cide.edu_sm151i2pdhu2371vq8hamcver4@group.calendar.google.com/public/full?q="+encodeURI($(this).val()), {"alt" : "json"}, function(data) {
    SelectedDates = {};
    $.each(data.feed.entry, function(i, entry) {
    var key = entry.gd$when[0].startTime.substr(0, 10)
    var clave = entry.gd$when[0].endTime.substr(0, 10);
    if(key in SelectedDates === false || clave in SelectedDates === false) {
    SelectedDates[key] = [];
    SelectedDates[clave] = [];
    }
    SelectedDates[key].push(entry.title.$t);
    SelectedDates[clave].push(entry.title.$t);  
    });
    $('#cal').datepicker("refresh");
    });
    });

    $('#cal').datepicker(
    {
            beforeShowDay: function (date) {
            var r = [true, ""];
            if (SelectedDates === null) {
            r[1] = "Highlighted-unknown";
            }
                else {
                fechasPeriodo = [];
                for(var property in SelectedDates) {
                fechasPeriodo.push(new Date(property));
                //alert(property);
                }
                var key = $.datepicker.formatDate("yy-mm-dd", date);
                if(key in SelectedDates) {

                if(fechasPeriodo.length > 1) {
                r[1] = fechasPeriodo[0] <= date && date <= fechasPeriodo[1] ?"Highlighted"+SelectedDates[key][0].replace(/\s/g, "_"):"Highlighted-unknown";
                }
                else {
                r[1] = "Highlighted"+SelectedDates[key][0].replace(/\s/g, "_"); 
                }
                r[2] = SelectedDates[key].join(", ");
                }
            }
            return r;
}, 
        minDate : fechaDefecto,
        maxDate : fechaFin, 
        numberOfMonths: [3,3]   
    });
});

I'm hoping someone points out a cause, even if it's a criticism, because it's getting late.

I must say I tried this: r[1] = new Date(fechasPeriodo[0].getYear(), fechasPeriodo[0].getMonth(), fechasPeriodo[0].getDate()) <= date && date <= new Date(fechasPeriodo[1].getYear(),fechasPeriodo[1].getMonth(),fechasPeriodo[1].getDate()) ?"Highlighted"+SelectedDates[key][0].replace(/\\s/g, "_"):"Highlighted-unknown";

But didn't work either. May there be a problem in the way I'm representing the dates when I call new Date in the line fechasPeriodo.push(new Date(property)); and the way I'm comparing them?

Answer 1

It's just the difference between the UTC and non-UTC representation.

new Date('2014-01-30').toString(); //Wed Jan 29 2014 19:00:00
new Date('2014-01-30').toUTCString(); //Thu, 30 Jan 2014 00:00:00

Try fechasPeriodo[0].toUTCString(); and I'm pretty sure it will return what you expect.