JSFiddle - React, Tailwind, and code Playground

HTML

<form name='keypad_test' action='#'>
    <div>
        <label for='user_id'></label>
        <div class='col-sm-10'>
            <input type='password' id='user_id' name='user_id' class='keypad' />
        </div>
    </div>
</form>

JavaScript

$('form').submit(function (e) {
    var user_id_var = $('input.keypad').val();
    alert(serialize(user_id_var));
    e.preventDefault();
})
function serialize(mixed_value) {
    //  discuss at: http://phpjs.org/functions/serialize/
    // original by: Arpad Ray (mailto:[email protected])
    // improved by: Dino
    // improved by: Le Torbi (http://www.letorbi.de/)
    // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net/)
    // bugfixed by: Andrej Pavlovic
    // bugfixed by: Garagoth
    // bugfixed by: Russell Walker (http://www.nbill.co.uk/)
    // bugfixed by: Jamie Beck (http://www.terabit.ca/)
    // bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net/)
    // bugfixed by: Ben (http://benblume.co.uk/)
    //    input by: DtTvB (http://dt.in.th/2008-09-16.string-length-in-bytes.html)
    //    input by: Martin (http://www.erlenwiese.de/)
    //        note: We feel the main purpose of this function should be to ease the transport of data between php & js
    //        note: Aiming for PHP-compatibility, we have to translate objects to arrays
    //   example 1: serialize(['Kevin', 'van', 'Zonneveld']);
    //   returns 1: 'a:3:{i:0;s:5:"Kevin";i:1;s:3:"van";i:2;s:9:"Zonneveld";}'
    //   example 2: serialize({firstName: 'Kevin', midName: 'van', surName: 'Zonneveld'});
    //   returns 2: 'a:3:{s:9:"firstName";s:5:"Kevin";s:7:"midName";s:3:"van";s:7:"surName";s:9:"Zonneveld";}'

    var val, key, okey,
    ktype = '',
        vals = '',
        count = 0,
        _utf8Size = function (str) {
            var size = 0,
                i = 0,
                l = str.length,
                code = '';
            for (i = 0; i < l; i++) {
                code = str.charCodeAt(i);
                if (code < 0x0080) {
                    size += 1;
                } else if (code < 0x0800) {
                    size += 2;
                } else {
                    size += 3;
                }
            }
            return size;
      ...