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how do i get the current date and time from windows timezones

I have the following timezones:
when a user selects a timezone from the list how do i get whats the current time and date at that timezone? for example if i choose "Azores" i want to get the current date time for that area.
In moment i could use IANA timezones and pass the timezone like and format it to ("dddd, D MMM YYYY" )
moment().tz().guess;
but the user doesnt want to use IANA Timezones because they cant find some of the countries so i cant go with that option.
Is there a way i can determine the current datetime based on the timezones specified?
i also tried the following if i passed in the offset but that didnt work example:
moment().utcOffset("-01:00");
because its taking my local time and offsetting it so it doesnt give me the actual current datetime.

To get all available timezones:
How to get list of all timezones in javascript
const arr = Intl.supportedValuesOf('timeZone');
JS Date object is in UTC, so to get Date with timezone offset you can use
I want to get New York time in this JavaScript clock?
const date = new Date(new Date().toLocaleString("en-US", {timeZone: "America/New_York"}));

How to display times in different time zones using the offset value

I am trying to display the current moment in different time zones. I have tried to use native javascript and the moment-js package but it seems you require the time zone name (ex. "America/Toronto") to display the information I want. The problem is that the information I currently have is the timestamp in string format (see below for string format) from the desired timezone, and the city the timestamp belongs to. The problem with using the city to create my tz value is that one of the cities I want to display isn't in the IANA tz database (Calgary).
String timestamp:
2022-04-26T14:19:42.8430964-04:00
As can be seen I do have the time offset and I was hoping there was a way to convert this string in js to a Date object and then display the time using the offset in the correct time zone.
Note what I want to display is the following format:
12:19 pm MT
I know I could just parse out the string but I feel like this isn't the best practice, however I may be wrong.
Also note that I will have to get the time zone (ex. MT, ET it can also be MST, EST) using the offset.

you don't need moment here. JS can do this natively. Also moment is now deprecated.
Your IANA timezone is America/Edmonton. So it's simple to do. That date format is an ISO 8601 date format, so you can just pass it into the new Date constructor and it'll parse it correctly:
const iso8601 = '2022-04-26T14:19:42.8430964-04:00';
const date = new Date(iso8601);
console.log(date.toLocaleString('en-US', { timeZone: 'America/Edmonton' }));
It doesn't matter what timezone your input date is set, so long as it has the correct offset in the ISO date. Once it's a Date, the offset is irrelevant. E.g.:
const iso8601 = '2022-04-26T14:19:42.8430964Z';
const date = new Date(iso8601);
//time will now be 4 hours off above as the input date is UTC
console.log(date.toLocaleString('en-US', { timeZone: 'America/Edmonton' }));

How the .getTime() can preserve the original date dd/MM/yyyy?

I have a trouble. I have an angular Javascript application that is storing the dates in mysql with milliseconds, but in some moments the date is interpreted with one more or less day. For example:
If the user selects in the date picker: 03/02/2017, the application is saving this (in milliseconds) as 02/02/2017 or 04/02/2017. I believe it is due to the timezone. This is the way I'm using to convert the date in milliseconds:
var temp = $("#datetimeField").val().split("/");
var newDatetime = new Date(temp[2], temp[1] - 1, temp[0]).getTime();
As you can see, I know the day, the month and the year before store it in the database. Normally the date is stored and works well, but in some moment the date changes as I showed above. How can I always get temp[2]/temp[1]-1/temp[0] ??? from the stored milliseconds?

momentjs toDate() date return not same as format() date

I am using moment 2.16.0 and want starting days of month. There are different result of toDate() and format() method. Here is jsfiddle.
code:-
var time=moment().subtract(0,'months').startOf("month").format();
console.log(time); //2016-12-01T00:00:00+05:30
var time2=moment().subtract(0, 'months').endOf("month").format();
console.log(time2); //2016-12-31T23:59:59+05:30
var time=moment().subtract(0,'months').startOf("month").toISOString();
console.log(time); //2016-11-30T18:30:00.000Z here i want somethings like 2016-12-01T00:00:00.000Z
var time2=moment().subtract(0, 'months').endOf("month").toISOString();
console.log(time2); // 2016-12-31T18:29:59.999Z here i want somethings like 2016-12-31T59:59:59.000Z

All of your operations are using moment with local time except the toISOString, which will give you the string in UTC. Since your timezone is offset from UTC, naturally the local time string (from format) and the UTC time string (from toISOString) are very different.
here i want somethings like 2016-12-01T00:00:00.000Z
That would be a different time from what that Moment instance represents.
If you want something in an ISO-8601 format but in local time, you can use format with the appropriate set of formatting tokens, but you don't wan the Z at the end because, again, you're not dealing with UTC ("Zulu") time, you're dealing with local time.
moment().format("YYYY-MM-DDThh:mm:ss.SSS")

parsing a UTC ISO date to a local time date in javascript/jquery

I have tried to search for the answer already, and although I find answers that are very similar, I don't think they are exactly what I am looking for. Please forgive me if this is already answered elsewhere.
I am trying to parse an ISO date in javascript so that I can compare it to the client system date and display information depending on if the ISO date is before or after the client system date.
This was fine until I needed to support IE8 and now I am stuck.
I have created a function because I have three different dates that I need to do this to.
for example, my ISO date is: 2015-12-22T11:59 in UTC time.
but once my date is parsed, the full date is 11:59 in local time, no matter which time zone i test, it's always 11.59 in THAT time zone.
I know that the function I have created currently doesn't do anything with timezone, this is where I am stuck. I don't know what to add to get my end date to change as a reflection of the timezone of the clients machine.
any help or advice would be greatly appreciated.
I am not able to use something like moments.js because I have an upload restriction.
Jquery is available though. or plain javascript.
<script>
function setSaleContent() {
//creating a new date object that takes the clients current system time. so we can compare it to the dates stored in our array
var currentDate = new Date();
console.log(currentDate + " this is the clients date ");
//These variables actually come from an external array object, but I'm putting them in here like this for this example.
var destinations = {
freedate: "2015-12-16T11:59",
courierdate: "2015-12-22T11:59",
nextdaydate: "2015-12-23T11:59",
}
//fetch all the ISO dates from the array.
var freeDateISO = destinations["freedate"];
var courierDateISO = destinations["courierdate"];
var nextdayDateISO = destinations["nextdaydate"];
//I am creating this reusable function to split up my ISO date for the sake of IE8.. and create it into a date format that can be compared against another date. I know that this isn't doing anything with my timezone and that is where my problem lies.
function parseDate(str) {
var parts = /^(\d{4}).(\d{2}).(\d{2}).(\d{2}):(\d{2})/.exec(str);
if (parts) {
return new Date(parts[1], parts[2] - 1, parts[3], parts[4], parts[5]);
}
return new Date();
}
//I would like this date to change to reflect the time zone of the clients system time.
//currently returns the date at 11.59 regardless of timezone.
//If i was in GMT i would want it to say 11.59
//If i was in CT time I would like this to say 05.59
//If i was in Perth I would like this to say 19:59
var freeDate = parseDate(freeDateISO);
console.log(freeDate + " this is the converted date for IE")
}
window.onload = setSaleContent;

The simple solution is to append Z to the ISO date to indicate it is in UTC time, such as 2015-12-22T11:59Z.
When JavaScript parses that date as a string, it will then automatically convert the UTC date to the local time zone.
While this is simple enough with a parsing call in the form new Date(str);, it will not play nice with your parse call with numerical arguments targeting IE8 and other old browsers.
A polyfill for parsing ISO dates with timezone exists: Javascript JSON Date parse in IE7/IE8 returns NaN
This can replace your custom parseDate function after some modification to take an input string.
Alternatively, implement your own custom date manipulater to account for the local timezone using the .getTimezoneOffset() method on the newly created date, which gives the time zone offset in minutes, but you will have to come up with a method of utilising the offset such as adjusting hours and minutes, due to the limited methods of the JavaScript date object.