Want to use Ext. State. CookieProvider save some memory function of the grid to the cookie, but according to the official demo, doesn't work, didn't save to cookies, cannot achieve more memory function, the core code snippet below, seek guidance:

var cp=new Ext. State. CookieProvider ({
Expires, new Date (new Date (). The getTime () + (1000 * 60 * 60 * 24 * 30)),
Path: "/",
Domain: null
});
Ext state. Manager. SetProvider (cp);

Var grid=new Ext grid. GridPanel ({
Store: store,

stateful: true,
StateId: 'the grid '
});