Once upon a time, OmniWeb had a JavaScript Console. That feature was dropped in favor of WebKit's
Drosera JavaScript debugger. I just launched the copy of Drosera I installed last Spring ... and it crashed.
I now see
"Drosera has been replaced by an improved debugger built into the Web Inspector."
Safari 3.1.2 includes an optional Develop menu, with access to the Web Inspector and Error Console.
My search thru OmniWeb's menus, preferences and toolbar for JavaScript tools came up empty. Have I overlooked something?