IOS UIWebView: How to add listeners to DOM events?

Question

How can I add listeners to DOM events in UIWebView? For example for the following html:

Try it
         


        

Answer 1

Yes, you can do this with crafted url and UIWebViewDelegate methods.

First, to add event listener on button tag, you should execute javascript like below (after the page is loaded)

// In the UIWebViewDelegate
- (void)webViewDidFinishLoad:(UIWebView *)webView {
    if (/* when the loaded url is the target */) {
        NSString *js = @"document.getElementById('button').click = function() { window.location = 'my-protocol://dummmy.com/maybe/some/data';}";
        [webView stringByEvaluatingJavaScriptFromString: js];
    }
}

We bind a click event on the button, and when it's clicked, it will trigger a request to webView.

And the next thing we gotta do is to intercept the request and do what you want in ObjC.

// In the UIWebViewDelegate
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    if (/* when the url of the request is the crafted url */) {
        // call your objc method...
    }
}