What are some methods to debug Javascript inside of a UIWebView?

Question

I\'m trying to figure out why something with Javascript isn\'t working inside of a UIWebView. To my knowledge, there is no way to set a breakpoint inside of XCode for a js f

Answer 1

alert() certainly works for me.

However, you can also do lots of other things, like make your own DHTML alert that pops up in a layer. This can be nice because you can do multiple alerts to a single div, without stopping your app. You should also be able to write a stack trace to it (the stack trace is in the exception object, and you can always throw your own exceptions).

Alternatively, if running on the simulator your custom "alert()" could call into objective C, and display the string in the iPhone simulator's console window:

document.location.href = "http://debugger/" + 
   encodeURIComponent(outputString);   

and on the objective C side:

//--------------------------------------------------------------------
- (BOOL)webView:(UIWebView*)webView 
       shouldStartLoadWithRequest: (NSURLRequest*)req 
       navigationType:(UIWebViewNavigationType)navigationType {
    if ([[[req URL] host] isEqualToString:@"debugger"]){
        // do stuff with [[req URL] path] 
       }
}

That said, I have an app that is heavy on the UiWebView / javascript stuff, and I tend to do most javascript dev in Chrome (simulating what is necessary from the iPhone environment)