阻止UIWebView警报

Question

I have an app that opens webpages from a variety of domains. Some of those domains have embedded scripts that display alerts like You're the 1 millionth visitor to this website. You won >>nothing<<" You're the 1 millionth visitor to this website. You won >>nothing<<" .

I've decided to hijack window.alert method calls to do nothing so that no malicious alerts can be displayed by said websites.

I block the alerts in both - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType and - (void)webViewDidFinishLoad:(UIWebView *)webView to prevent websites displaying alerts before the page has finished loading.

Some crash reports indicate that calling webView stringByEvaluatingJavaScriptFromString:... from shouldStartLoadWithRequest causes the app to crash. Not always, just sometimes. Any idea why that might be?

Is there a way to prevent the alerts displaying in the first place without doing the manual hijacking? I'd love to use SFSafariViewController but that's not an option for various constraints unfortunately.

Answer 1

Why not use WKWebView? WKWebView hooks JS's alert and do nothing by default.

FYI:

If you want to show alert when JS's alert is called, implement WKUIDelegate's

webView(webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: () -> Void) 

and show dialog by yourself.