Reading parameters from URL - Javascript

Another simple, minimal Javascript snippet - how to read URL parameters.

    var PARAMETERS = {};
    PARAMETERS.load = function() {
        PARAMETERS.map = {};
        window.location.search.substring(1).replace(/([^&=]+)([=]([^&]*))?(&|$)/g,function(s,k,q,v){
            if (undefined === PARAMETERS.map[k]) {
                PARAMETERS.map[k] = [];
            }
            PARAMETERS.map[k].push(decodeURIComponent(v));
        });
        for (var k in PARAMETERS.map) {
            var a = PARAMETERS.map[k];
            PARAMETERS.map[k] = ((1 == a.length) ? a[0] : a);
        }
    };
    PARAMETERS.load();

That's all. Value for the parameter "who" is found at PARAMETERS.map.who already decoded. Repeated parameters are turned into an array, i.e.: "?a=1&a=2&a=3" becomes [1,2,3].

Try it out on the test page. Code can be found in base.js.