I have a solution to log, using javascript, to the apps debug console.
It's a bit crude, but it works.

First, we define the console.log() function in javascript, which opens and immediately removes an iframe with a ios-log: url.

// Debug

console = new Object();

console.log = function(log) {

  var iframe = document.createElement(IFRAME);

  iframe.setAttribute(src, ios-log:#iOS# + log);

  document.documentElement.appendChild(iframe);

  iframe.parentNode.removeChild(iframe);

  iframe = null;    

};

console.debug = console.log;

console.info = console.log;

console.warn = console.log;

console.error = console.log;

Now we have to catch this URL in the UIWebViewDelegate in the iOS app using the shouldStartLoadWithRequest function.

- (BOOL)webView:(UIWebView *)webView2 

shouldStartLoadWithRequest:(NSURLRequest *)request 

 navigationType:(UIWebViewNavigationType)navigationType {



    NSString *requestString = [[[request URL] absoluteString] stringByReplacingPercentEscapesUsingEncoding: NSUTF8StringEncoding];

    //NSLog(requestString);



    if ([requestString hasPrefix:@ios-log:]) {

        NSString* logString = [[requestString componentsSeparatedByString:@:#iOS#] objectAtIndex:1];

                               NSLog(@UIWebView console: %@, logString);

        return NO;

    }



    return YES;

}