I think this would be a good addition to jQuery core, because most people use or might want to use URL parameters in their Javascript. This function makes it really easy:

//returns the requested GET parameter from the URL
url: function(param) {
    var regex = '[?&]' + param + '=([^&#]*)';
    var results = (new RegExp(regex)).exec(window.location.href);
    if(results) return results[1];
    return '';
}