JS namespacing function

String.prototype.namespace = function(properties) {
    var ns = this.split('.'),
            o = window,
            i,
            len;
    for (i = 0,len = ns.length; i < len; i++) {
        o = o[ns[i]] = o[ns[i]] || {};
    }
 
    for (prop in properties) {
       o[prop] = properties[prop];
    }
    
 
    return o;
};