JSFiddle - React, Tailwind, and code Playground

by efwjames

HTML

<input type="text" id="phone" maxlength="11">

JavaScript

var phone = "6129872395";
$('#phone').keyup(function (e) {
    var currentval = $(this).val();

    if (e.keyCode == 46) {} else {
        if (currentval.length == 4 && $(this).val().charAt(3) !== ' ') {
            $(this).val(currentval.substr(0,3) + ' ' + currentval.charAt(3));
        } else {
            $(this).val(currentval);
        }
    }

});