I need to have my iPhone Objective-C code catch Javascript errors in a UIWebView. That includes uncaught exceptions, syntax errors when loading files, undefined variable references, etc.
This is for a development environment, so it doesn't need to be SDK-kosher. In fact, it only really needs to work on the simulator.
I've already found used some of the hidden WebKit tricks to e.g. expose Obj-C objects to JS and to intercept alert popups, but this one is still eluding me.
[NOTE: after posting this I did find one way using a debugging delegate. Is there a way with lower overhead, using the error console / web inspector?]
Best Answer
I have now found one way using the script debugger hooks in WebView (note, NOT UIWebView). I first had to subclass UIWebView and add a method like this:
Next you should create a YourScriptDebugDelegate class that contains methods like these:
There is probably a large runtime impact for this, as the debug delegate can also supply methods to be called for entering and exiting a stack frame, and for executing each line of code.
See http://www.koders.com/noncode/fid7DE7ECEB052C3531743728D41A233A951C79E0AE.aspx for the Objective-C++ definition of WebScriptDebugDelegate.
Those other methods:
Note that this is all hidden away in a private framework, so don't try to put this in code you submit to the App Store, and be prepared for some hackery to get it to work.