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How to subtract two different dates from a date/time stamp?

I need to subtract a date like 1/26/2015 from a date-time like 2016-01-27T01:10:57.569000+00:00. From what I've read converting both to distance in milliseconds from Epoch and then subtracting is the easiest way. I've tried using various methods, but all the methods seem to say 2016-01-27T01:10:57.569000+00:00 is invalid data. The method .getTime() works great for the 1/26/2015 format, but it can't read the 2016-01-27T01:10:57.569000+00:00.
How does one go about getting the date/time UTC time into milliseconds?

On a complicated way you can use a regex to extract each part of the date as string and then use them in a new Date with all parameters:
function getTimeDifference(){
var regEx = /(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):([\d.]+)/;
var dateString = '2016-01-27T01:10:57.569000+00:00';
var r = regEx.exec( dateString );
var date1 = new Date(r[1], r[2]-1, r[3], r[4], r[5], r[6]); // Notice the -1 in the month
var date2 = new Date('1/26/2015');
var difference = date1 - date2;
Logger.log(difference);
}

I ended up using this. When I call parseDate(), I used getTime() to get the date in milliseconds then subtracted them and converted them to days. For my use case the time didn't have to be down to the second, but if it did, it wouldn't be hard to parse more info from the string. I ran into trouble initially because as a beginner Javascript writer I didn't know why apps script wouldn't accept this format into the date constructor.
function parseDate(str) {
//This should accept 'YYYY-MM-DD' OR '2016-01-27T01:10:57.569000+00:00'
if(str.length == 10){
var mdy = str.split('-');
return new Date(mdy[0], mdy[1]-1, mdy[2]);
}
else
{
var mdy = str.split('-');
var time = mdy[2].split('T');
var hms = time[1].split(':');
return new Date(mdy[0], mdy[1]-1, time[0], hms[0], hms [1]);
}
}

If you are confident that the values in the date strings will always be valid and that the ISO8601 string will always have offset 00:00 (i.e. UTC), then simple parse functions are:
// Parse ISO 8601 format 2016-01-27T01:10:57.569000+00:00
function parseISOUTC(s) {
var b = s.split(/\D/);
return new Date(Date.UTC(b[0],b[1]-1,b[2],b[3],b[4],b[5],b[6]));
}
document.write(parseISOUTC('2016-02-04T00:00:00.000+00:00'));
// Parse US format m/d/y
function parseMDY(s) {
var b = s.split(/\D/);
return new Date(b[2],b[0]-1,b[1]);
}
document.write('<br>'+ parseMDY('2/4/2016'))
document.write('<br>'+ (parseISOUTC('2016-02-04T00:00:00.000+00:00') - parseMDY('2/4/2016')))
Note that the first string is UTC and the second will be treated as local (per ECMAScript 2015), so the difference between 2016-02-04T00:00:00.000+00:00 and 2/4/2016 will be the time zone offset of the host system.

Changing date format javascript

I'm pulling some data from two different APIs and I want to the objects later on.
However, I'm getting two different date formats: this format "1427457730" and this format "2015-04-10T09:12:22Z". How can I change the format of one of these so I have the same format to work with?
$.each(object, function(index) {
date = object[index].updated_at;
}

Here's one option:
var timestamp = 1427457730;
var date = new Date(timestamp * 1000); // wants milliseconds, not seconds
var dateString = date.toISOString().replace(/\.\d+Z/, 'Z'); // remove the ms
dateString will now be 2015-03-27T12:02:10Z.

Try moment.js
var timestamp = 1427457730;
var date = '2015-04-10T09:12:22Z';
var m1 = moment(timestamp);
var m2 = moment(date);
console.log(m1);
console.log(m2);
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.11.1/moment.min.js"></script>
You can use .format() method in moment to parse the date to whatever format you want, just like:
m2.format('YYYY MMM DD ddd HH:mm:ss') // 2015 Apr 10 Fri 17:12:22
Check out the docs for more format tokens.

What you probably want in javascript, are date objects.
The first string is seconds since epoch, javascript needs milliseconds, so multiply it by 1000;
The second string is a valid ISO date, so if the string contains a hyphen just pass it into new Date.
var date = returned_date.indexOf('-') !== -1 ? returned_date : returned_date * 1000;
var date_object = new Date(date);
Making both types into date objects, you could even turn that into a handy function
function format_date(date) {
return new Date(date.indexOf('-') !== -1 ? date : date * 1000);
}
FIDDLE

Take a look at http://momentjs.com/. It is THE date/time formatting library for JavaScript - very simple to use, extremely flexible.

Javascript - Convert string to date and compare dates

I have date from the date picker which I am accessing as -
var transdate = $j("input[name='enterdate']").val();
resulting in transdate = "6/22/2015"
I need to test if the entered date is between two dates which are defined as
startdate = '2015-02-01' and enddate = '2015-07-30'
How do I convert the transdate in yyyy-mm-dd format in the following code -
if ((new Date('transdate')>= startdate ) && (new Date('transdate') <= enddate )) {
alert("correct date entered");
}

Moment.js is a small handy library for dates that makes this easy.
moment('6/22/2015', 'M/D/YYYY')
.isBetween('2015-02-01', '2015-07-30'); // => true
Note that only the first (US format) date string needed an explicit format string supplied.
Moment can be useful for the parsing alone, eg. even if not using isBetween:
var transdate = moment('6/22/2015', 'M/D/YYYY').toDate();
var startdate = moment('2015-02-01').toDate();
var enddate = moment('2015-07-30').toDate();
transdate >= startdate && transdate <= enddate // => true

The string is not in the only format defined to be handled by the Date object. That means you have to parse it (with regular expressions or String#split or whatever), or use a library like MomentJS that will parse it for you. Once you've parsed the dates, you can compare them with < or >, etc.
Do not rely on Date to parse strings it's not defined to parse. You will run into implementations or locales where it doesn't work.
"6/22/2015" is trivial to parse with a regular expression:
var rex = /^(\d+)\/(\d+)\/(\d+)$/;
var match = rex.exec(transdate);
var dt = match ? new Date(+match[3], +match[1] - 1, +match[2]) : null;
That uses the Date constructor that accepts the parts of the date as individual numeric arguments (year, month, day). The + converts strings to numbers. The [x] are capture groups from the regex. You have to subtract one from the month because months start with 0 in JavaScript.

Similar questions have been asked many, many times but I can't seem to find a duplicate. Given the unreliability of the Date constructor to parse strings, the simplest solution is to parse the string yourself:
function parseMDY(s) {
var b = s.split(/\D/);
return new Date(b[2], b[0]-1, b[1]);
}

Here is the JSFIDDLE of you output.
Moment.js will give you good flexibility in coding.
Dont forget to add jquery and moment.js in your html
var transdate="6/22/2014";
var convertStringToValidDate = new Date(transdate);
$(document).ready(function(){
$("#selectedDate").text(transdate);
$("#validDate").text(convertStringToValidDate);
converttoformat = moment(convertStringToValidDate).format("YYYY-MM-DD");
$("#converttoyyyymmdd").text(converttoformat);
if(moment(converttoformat).isBetween('2015-02-01', '2015-07-30')){
$("#result").text("Date lies in between");
}
else{
$("#result").text("Date is out of scope");
}
});

Reading the date from textbox as a string and converting it into as Date

I am reading the date from textbox by using javascript and trying to convert it as Date object.But my problem is date is converting as month and month is converting as date when converting the string to date.
Example:
03/12/2014 the value in the textbox
Actual Output:
03 as March,
12 as date (Its wrong)
Expected Output:
03 as date
12 as December (I am expecting)
While converting this string to date by using following snippet
var startTime = document.getElementById("meeting:startTime");
date.js
var stringToDate_startTime=new Date(Date.parse(startTime.value,"dd/mm/yy"));
moment.js
var date1=moment(startTime.value).format('DD-MM-YYYY');
In the above even i have used date.js and moment.js files also.But those also did not solve my problem.Please can anyone help me out to get rid out of this.

Try ...
var from = startTime.value.split("/");
var newDate = newDate(from[2], from[1] - 1, from[0]);
... assuming time included ...
var date_only = startTime.value.split("");
var from = date_only[0].split("/");
var newDate = newDate(from[2], from[1] - 1, from[0]);

I am not aware of an implementation of the Date.parse() method that accepts two arguments. You can view the Mozilla Date.parse() method description here Date.parse() - JavaScript | MDN.
It might be worth looking at the question/answer of this question for some more information: Why does Date.parse give incorrect results?
The next best option would be to split the date using String.split() and to rearrange the date parts
var dateStr = '03/12/2014 23:05';
var newDateStr = null;
var dateParts = dateStr.split('/');
if (dateParts.length == 3) {
var day = dateParts[0];
var month = dateParts[1];
var yearAndTime = dateParts[2];
// Rearrange the month and day and rejoin the date "12/03/2014 23:05"
newDateStr = [ month, day, yearAndTime].join('/');
} else {
throw new Error('Date not in the expected format.');
}
var date = new Date(newDateStr); // JS Engine will parse the string automagically
alert(date);
This isn't the most elegant solution, but hopefully that helps.

How to create a date object from string in javascript [duplicate]

This question already has answers here:
Parsing a string to a date in JavaScript
(35 answers)
Closed 5 years ago.
Having this string 30/11/2011. I want to convert it to date object.
Do I need to use :
Date d = new Date(2011,11,30); /* months 1..12? */
or
Date d = new Date(2011,10,30); /* months 0..11? */
?

var d = new Date(2011,10,30);
as months are indexed from 0 in js.

You definitely want to use the second expression since months in JS are enumerated from 0.
Also you may use Date.parse method, but it uses different date format:
var timestamp = Date.parse("11/30/2011");
var dateObject = new Date(timestamp);

The syntax is as follows:
new Date(year, month [, day, hour, minute, second, millisecond ])
so
Date d = new Date(2011,10,30);
is correct; day, hour, minute, second, millisecond are optional.
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date

There are multiple methods of creating date as discussed above. I would not repeat same stuff. Here is small method to convert String to Date in Java Script if that is what you are looking for,
function compareDate(str1){
// str1 format should be dd/mm/yyyy. Separator can be anything e.g. / or -. It wont effect
var dt1 = parseInt(str1.substring(0,2));
var mon1 = parseInt(str1.substring(3,5));
var yr1 = parseInt(str1.substring(6,10));
var date1 = new Date(yr1, mon1-1, dt1);
return date1;
}

Very simple:
var dt=new Date("2011/11/30");
Date should be in ISO format yyyy/MM/dd.

First extract the string like this
var dateString = str.match(/^(\d{2})\/(\d{2})\/(\d{4})$/);
Then,
var d = new Date( dateString[3], dateString[2]-1, dateString[1] );

Always, for any issue regarding the JavaScript spec in practical, I will highly recommend the Mozilla Developer Network, and their JavaScript reference.
As it states in the topic of the Date object about the argument variant you use:
new Date(year, month, day [, hour, minute, second, millisecond ])
And about the months parameter:
month Integer value representing the month, beginning with 0 for January to 11 for December.
Clearly, then, you should use the month number 10 for November.
P.S.: The reason why I recommend the MDN is the correctness, good explanation of things, examples, and browser compatibility chart.

I can't believe javascript isn't more consistent with parsing dates. And I hear the default when there is no timezone is gonna change from UTC to local -- hope the web is prepared ;)
I prefer to let Javascript do the heavy lifting when it comes to parsing dates. However it would be nice to handle the local timezone issue fairly transparently. With both of these things in mind, here is a function to do it with the current status quo -- and when Javascript changes it will still work but then can be removed (with a little time for people to catch up with older browsers/nodejs of course).
function strToDate(dateStr)
{
var dateTry = new Date(dateStr);
if (!dateTry.getTime())
{
throw new Exception("Bad Date! dateStr: " + dateStr);
}
var tz = dateStr.trim().match(/(Z)|([+-](\d{2})\:?(\d{2}))$/);
if (!tz)
{
var newTzOffset = dateTry.getTimezoneOffset() / 60;
var newSignStr = (newTzOffset >= 0) ? '-' : '+';
var newTz = newSignStr + ('0' + Math.abs(newTzOffset)).slice(-2) + ':00';
dateStr = dateStr.trim() + newTz;
dateTry = new Date(dateStr);
if (!dateTry.getTime())
{
throw new Exception("Bad Date! dateStr: " + dateStr);
}
}
return dateTry;
}
We need a date object regardless; so createone. If there is a timezone, we are done. Otherwise, create a local timezone string using the +hh:mm format (more accepted than +hhmm).