A while ago I posted this software wish:
… if only there were a tool that would let me search inside the text that I am posting to input boxes on web forms before I actually post it.
Well, my wish has been almost answered by the Firefox textareatools extension.
I say “almost answered” because this extension still has rough edges, e.g. “find” doesn’t actually work for me — I have to use the “find (regexp)” option for it to do anything. It could use better shortcuts, especially one to repeat a search. But oh am I happy to have it.