zlacker

I'm not sure if it always works on all APIs or browsers, but you can wrap and replace DOM API objects with logging proxies.

Additionally, you can set breakpoints on event handlers and Chromium has deobfuscation built in. You can usually tell approximately what's going on by stepping through the code and watching the variables in local scope.

>>TJSome+(OP)
> but you can wrap and replace DOM API objects with logging proxies.

Right, so you are describing the implementation of the tool I was looking for. Obviously I don't want to do that manually while tracing a page.