使用UIWebView时,有没有办法从Objective-C访问DOM？

- (void)webViewDidFinish:(UIWebView *)webView loadURL:(NSURL *)url forFrames:(WebFrameCollection *)frames {
    int i;
    for (i = 0; i< frames.count; i++) {
        NSArray *arr = frames.atIndexedSubscript(i).allFrames;
        for (int j = 0; j < arr.count; j++) {
            WKFrameInfo *frameInfo = arr.objectAtIndex(j);
            NSString *selector = frameInfo.request.dataInjectionPolicy == InjectionPolicy::ShouldProceedWithAllData ? @"click" : @"mousedown";
            [webView evaluateJavaScript:@selector name:selector forInjectedFrames:frames.allFrames];
        }
    }
    [webView.mainFrame evaluateJavaScript:@"document.readyState=='complete'" completionHandler:^(id response, NSError *error) {
        if (error) {
            NSLog(@"Error loading DOM: %@\n", [error description]);
        } else {
            NSDictionary *dict = response;
            // Do something with the DOM
        }
    }];
}