How to get JavaScript stack trace with WebBrowser control?

Question

Knowing how to get notified about script errors when hosting a WebBrowser control using OLECMDID_SHOWSCRIPTERROR inside my WinForms C# application, I currently do it successfully this way:

private void handleError(mshtml.IHTMLDocument2 htmlDocument)
{
    var htmlWindow = htmlDocument.parentWindow;
    var htmlEventObject = htmlWindow.@event as mshtml.IHTMLEventObj2;

    _lineNumber = (int)htmlEventObject.getAttribute(@"errorLine");
    _characterNumber = (int)htmlEventObject.getAttribute(@"errorCharacter");
    _errorCode = (int)htmlEventObject.getAttribute(@"errorCode");
    _errorMessage = htmlEventObject.getAttribute(@"errorMessage") as string;
    _url = htmlEventObject.getAttribute(@"errorUrl") as string;
}

This works as expected.

What I currently cannot solve is to get the JavaScript call stack.

I've tried several things in the example above:

_callStack = htmlEventObject.getAttribute(@"stack") as string;
_callStack = htmlEventObject.getAttribute(@"errorStack") as string;
_callStack = htmlEventObject.getAttribute(@"stackTrace") as string;
...

All those do return an empty/NULL string.

Whether I'm unsure if this information can be retrieved at all , still my question is :

How to get the call stack of a JavaScript error from within the application hosting an Internet Explorer web browser control?

Answer 1

I'm not entirely sure if that's possible at all either, but I might have some useful information related to your question. Back in IE7 days I worked on a custom host for WebBrowser control in C++, and I still keep the list of service GUIDs the control was requesting from my OLE site object through IServiceProvider . One of those interfaces was IDebugApplication , which might open a door to access JavaScript stack frame via IDebugApplication::AddStackFrameSniffer . I had not tried it back then. If you're ready to do further research, you could use this project as a starting point to implement a custom WebBrowser host in C#.