Parse x-www-form-urlencoded to Json object

FormURLEncodedToJSON.js

function FormURLEncodedToJSON(str) {
    "use strict";
    var obj, i, pt, keys, j, ev;

    if (typeof FormURLEncodedToJSON.br !== 'function') {
        FormURLEncodedToJSON.br = function(repl) {

            if (repl.indexOf(']') !== -1) {
                return repl.replace(/\](.+?)(,|$)/g, function($1, $2, $3) {
                    return FormURLEncodedToJSON.br( $2 + '}' + $3 );
                });
            }
            return repl;
        };
    }
    str = '{"' + (str.indexOf('%') !== -1 ? decodeURI(str) : str) + '"}';

    obj = str.replace(/\=/g,'":"').replace(/&/g,'","').replace(/\[/g,'":{"');

    obj = JSON.parse(
        obj.replace(/\](.+?)(,|$)/g, function($1,$2,$3) { 
            return FormURLEncodedToJSON.br( $2 + '}' + $3);
        })
    );

    pt = ('&' + str).replace(/(\[|\]|\=)/g,'"$1"').replace(/\]"+/g,']').replace(/&([^\[\=]+?)(\[|\=)/g,'"&["$1]$2');

    pt = (pt + '"').replace(/^"&/,'').split('&');

    for (i=0; i<pt.length; i++) {
        ev = obj;
        keys = pt[i].match(/(?!:(\["))([^"]+?)(?=("\]))/g);

        for (j=0; j<keys.length; j++) {

            if ( !ev.hasOwnProperty(keys[j])) {

                if (keys.length > (j + 1)) {
                    ev[keys[j]] = {};
                }
                else {
                    ev[keys[j]] = pt[i].split('=')[1].replace(/"/g,'');
                    break;
                }
            }
            ev = ev[keys[j]];
        }
    }
    return obj;
}