将时区偏移量应用于js代码

Question

I am trying to compare the current time to some timestring variables I have in my db.

I had the following code working but the time on my server changed and now it no longer works.

var d = new Date();
var day = d.getDate();
if ((day.toString()).length == 1){
    day='0'+day;
}
var month = d.getMonth()+1;
if ((month.toString()).length == 1){
    month='0'+month;
}


var mins = d.getMinutes()+100;
console.log("mins is " + mins);
var timeVar = (d.getHours() * 100) + mins;

//concatenated string version of the var
var currtime = year+month+day+timeVar;

I know if I call d.getTimezoneOffset(), I get -240 and that is exactly my issue, I am 4 hours off. But I cant apply that value in the right way to my code.

Right now my variable for currTime returns:

20150707242 but I need it to return 20150 7 072 2 42

Any help appreciated.

UPDATE

I was about to get the correct timeVar using:

var d2 = new Date(new Date().getTime() + (d.getTimezoneOffset() * 1000));
var hrs2 = d2.getUTCHours();
var mins2 = d2.getUTCMinutes();

console.log("hrs2 = " + (hrs2+1) + " mins2 = "+ (mins2 + 4));

var actualHrs = hrs2+1;
var actualmins = mins2 +4;
var currtime = year+month+day+actualHrs+actualmins;

But now my issue exists with my day variable created as such:

var d = new Date();
var day = d.getDate();
if ((day.toString()).length == 1){
    day='0'+day;
}

Because my time retrieved is 4 hrs ahead, it thinks my current day is tomorrow.

Can anyone help me get around this?

Answer 1

You can use var a = Date(timestamp) to generate the correct date oject, which is internally the number of millisecond from 01-01-1970.

Confronting two date object is a simple subtraction

var a = new Date();
var b = new Date(timestring);
var delta = a - b // a signed integer

more on parsing dates from timestring

As you already did this

var d2 = new Date(new Date().getTime() + (d.getTimezoneOffset() * 1000));

is kind of a good way to deal with your problem of timezones