window.location.querystring = (function() {

    // by Chris O'Brien, prettycode.org

    var collection = {};

    // Gets the query string, starts with '?'

    var querystring = window.location.search;

    // Empty if no query string

    if (!querystring) {
        return { toString: function() { return ""; } };
    }

    // Decode query string and remove '?'

    querystring = decodeURI(querystring.substring(1));

    // Load the key/values of the return collection

    var pairs = querystring.split("&");

    for (var i = 0; i < pairs.length; i++) {

        // Empty pair (e.g. ?key=val&&key2=val2)

        if (!pairs[i]) {
            continue;
        }

        // Don't use split("=") in case value has "=" in it

        var seperatorPosition = pairs[i].indexOf("=");

        if (seperatorPosition == -1) {
            collection[pairs[i]] = "";
        }
        else {
            collection[pairs[i].substring(0, seperatorPosition)]
                = pairs[i].substr(seperatorPosition + 1);
        }
    }

    // toString() returns the key/value pairs concatenated

    collection.toString = function() {
        return "?" + querystring;
    };

    return collection;
})();