iOS开发 创建自己的UserAgent

- (void)createNewUserAgent{    UIWebView* tempWebView = [[UIWebView alloc] initWithFrame:CGRectZero];    NSString* userAgent = [tempWebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];    NSString *version = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];    NSString *myAgent = [NSString stringWithFormat:@"%@ xxx/%@",userAgent,version];    NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:myAgent, @"UserAgent", nil];    [[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];}