Obtener los parametros de una url

var urlParams;
(window.onpopstate = function () {
    var match,
        pl     = /+/g,
        search = /([^&=]+)=?([^&]*)/g,
        decode = function (s) { return decodeURIComponent(s.replace(pl, " ")); },
        query  = window.location.search.substring(1);
 
    urlParams = {};
    while (match = search.exec(query))
       urlParams[decode(match[1])] = decode(match[2]);
})();

urlParams = {
    nombre: "Juan",
    apellido1: "Lopez",
    apellido2: "Martinez",
    id: "12221"
}
 
alert(urlParams["nombre"]);