iOS清理WebView的缓存

    NSHTTPCookie *cookie;
    NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
    for (cookie in [storage cookies]){
          [storage deleteCookie:cookie];
    }  

   //清除UIWebView的缓存
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
     NSURLCache * cache = [NSURLCache sharedURLCache];
     [cache removeAllCachedResponses];
     [cache setDiskCapacity:0];
     [cache setMemoryCapacity:0];