Javascript - URL Params Anonymous function Object

gistfile1.txt

var urlParams = {};
(function() {
 
    var match,
        pl     = /\+/g,  // Regex for replacing addition symbol with a space
        search = /([^&=]+)=?([^&]*)/g,
        decode = function (s) { return decodeURIComponent(s.replace(pl, " ")); },
        query  = window.location.search.substring(1).toLowerCase();
 
    while (match = search.exec(query))
       urlParams[decode(match[1])] = decode(match[2]);
 
}());
 
//Usage urlParams['q'];