How to ignore javascript timezone to send a datetime to server

If you are using .Net Web API as backend, you can config the timezone in Web API WebApiconfig.cs like below. It will serialize the time in UTC.

public static void Register(HttpConfiguration config)
{
    config.Formatters.JsonFormatter.SerializerSettings.DateTimeZoneHandling = Newtonsoft.Json.DateTimeZoneHandling.Utc;
}

So if you are using html5 datetime,then you can change it to datetime-local

<input type="datetime-local">

This will give you datetime without the timezone info.

Here is an example.

var dateControl = document.querySelector('input[type="datetime-local"]');
dateControl.value = '2017-06-01T08:30';

let btn = document.getElementById('btns');
let inp = document.getElementById('party');
let dv = document.getElementById('displayValue');
btn.addEventListener('click', ()=>{
  dv.innerText = inp.value;
});

<label for="party">Enter a date and time for your party booking:</label>
<input id="party" type="datetime-local" name="partydate" value="2017-06-01T08:30">

<button type="submit" id="btns">Check Value</button>

<div id="displayValue">
  
</div>

Code snippet is just to give you an idea on how to use datetime-local. If you are using angular 2/4, then you can directly bind ngModel to a variable as you would do generally to get the value.