Answer by Chandrakanth M for Getting the client's time zone (and offset) in JavaScript

function getLocalTimeZone() {    var dd = new Date();    var ddStr = dd.toString();    var ddArr = ddStr.split('');    var tmznSTr = ddArr[5];    tmznSTr = tmznSTr.substring(3, tmznSTr.length);    return tmznSTr;}

Example : Thu Jun 21 2018 18:12:50 GMT+0530 (India Standard Time)

O/P : +0530