Capturing Javascript Alert in Webbrowser Control

Question

Using the webbrowswer control to cruise a site. Sometimes errors occur which involve a javascript popup box. I would like to do a couple of things when this happens.

Answer 1

Just do this:

window.alert = function(txt) {
   // Do something
}

This will allow you to do a callback or anything else you want with the alert text.

Answer 2

If you're looking to only trap script error dialogs that appear, I would recommend trapping the window.onerror DOM event. If you assign a handler for this event, the message, (script) file name and line number are passed as arguments, those are all things shown in the error dialog that pops up. Note that most users have scripting error dialogs switched off by default so it would be wise to honour this if the intended purpose is for a large audience.

I'm not sure if there's an easier way, I've only worked with the old COM WebBrowser component.