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

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 file. No problemo, I'll just go back to 2004 and use alert statemen-- oh wait they don't seem to work inside of a UIWebView either!

The only thing I could think of is by exporting my HTML And JS files to my desktop and then just doing my debugging inside of Safari. And that works! But of course, the bug I'm fighting with in the UIWebView doesn't occur in Safari.

Are there any other ways for debugging inside of a UIWebView, or any tricks that I can use akin to using the old-school alert method?

If you're using iOS >= 6 and you have mountain lion (10.8) or Safari >= 6, you can just:

1. Open the application in the simulator (or your device in XCode >= 4.5.x).
2. Open Safari (go to Preferences -> Advanced and make sure "Show Develop Menu in Menubar" is on.
3. From the Menu-bar (of Safari) select Develop -> iPhone Simulator -> [your webview page].

That's it !

This query tops google, so worth linking to the remoteInspector hidden in iOS5 - by far the best way found so far to debug your UIWebViews - just conditional compile out before you send to Apple.

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)

> I get the awesome way to debug UIWebView Or > SFSafariViewController.

I hope It will Help.

Step 1: 
 Open Safari VC In Your Mac (hahaha Don't make your face, If I am saying in your Macbook just follow this my steps)



Step2: Go at Safari preferences And Click on Advance. 

You will Get this setting on your MacBook Screen.

Now enable the Show to develop menu in menu bar.

 Now Your All work is done. 

Are you thinking I am kidding :P :P no man... 



Step3: Run your application in Device or Simulator. (Don’t Think Just run )
And go in your application where you are opening your Webview or SFSafariViewController. 
 Till now you did not understand I know. Be cool and see my next step.


Step4: Open Safari In your MacBook and Click on Develop Option from the Menu bar. 

Did you get something your MacBook, iPad/ iPhone is Displaying Right?????



Step5: Its Done. click your device and click on URL New popup will come out like This.




Step6: what are you looking now its over here all the steps.

> Now debug your Webpage on this console. > Be happy and enjoy your day while doing coding With a cup of tea or > Coffee.

IMP: Don't forget to enable See Below Image 








I haven't tried this yet, but take a look at this Weinre

Looks very promising.

This is an old question. But I'll still like to share my two cents.

I have been using jsconsole.com for remote debugging. It's easy. Just include a script tag and use console logs to debug by printing. This can also be used for debugging on a real device.

Old question, but I think I found the best solution, in my case you need to debug uiwebview, but I had no access to the IOS app and only to the html content and I had to view some JS logs, I added the following code to load the light firebug JS and show it automatically:

calling it from JS

var script = document.createElement('script');
script.type = 'text/javascript';
script.src = 'https://getfirebug.com/firebug-lite-debug.js';
document.head.appendChild(script);

or load it from html

<script type="text/javascript" src="https://getfirebug.com/firebug-lite-debug.js"></script>

You can set up a system like that used in PhoneGap to send messages from JavaScript to Objective-C and log from there. In a nutshell, they are setting document.location with a custom scheme and blocking that scheme in the delegate callback.

You can take advantage of the fact that a UIWebView is most of the delegates for a WebView. WebKit is technically undocumented for iPhone, but mostly the same as specified in the desktop WebKit headers, possibly including the WebScriptObject. I use this for debugging, but be sure to strip this code out before submitting to Apple.

To get a WebView from a UIWebView, implement a delegate method like -(void) webView:(id)inWebView didFinishLoadForFrame:(id)inWebFrame in a subclass of UIWebView. Call super if you use that one.