Timezone in hours-
var offset = new Date().getTimezoneOffset();if(offset<0) console.log( "Your timezone is- GMT+"+ (offset/-60));else console.log( "Your timezone is- GMT-"+ offset/60);If you want to be precise as you mentioned in comment, then you should try like this-
var offset = new Date().getTimezoneOffset();if(offset<0){ var extraZero = ""; if(-offset%60<10) extraZero="0"; console.log( "Your timezone is- GMT+"+ Math.ceil(offset/-60)+":"+extraZero+(-offset%60));}else{ var extraZero = ""; if(offset%60<10) extraZero="0"; console.log( "Your timezone is- GMT-"+ Math.floor(offset/60)+":"+extraZero+(offset%60));}