[webView loadRequest: [NSURLRequest requestWithURL: [NSURL URLWithString: url]
NSURLRequestCachePolicy defines constants that are used to specify interaction with the cached responses.
Specifies that the caching logic defined in the protocol implementation, if any, is used for a particular URL load request. This is the default policy for URL load requests.
Specifies that the data for the URL load should be loaded from the originating source. No existing cache data should be used to satisfy a URL load request.
Specifies that the existing cached data should be used to satisfy the request, regardless of its age or expiration date. If there is no existing data in the cache corresponding the request, the data is loaded from the originating source.
Specifies that the existing cache data should be used to satisfy a request, regardless of its age or expiration date. If there is no existing data in the cache corresponding to a URL load request, no attempt is made to load the data from the originating source, and the load is considered to have failed. This constant specifies a behavior that is similar to an “offline” mode.