I spend much time using the Firebug command line set in multiple lines view, I edit javascript code or run little not automated tests copying and pasting code to the Firebug command line window.
Copy and paste doesn’t really fits my needs, I prefer to edit javascript files from my preferred editor (i.e. KomodoEdit) than run them on Firebug especially if code consists of many lines (more than dozen) so I’ve added to Firebugย the ability to open and save files extending ViewSourceWith
Now it’s possible to open/save files directly from Firebug but the most important feature allows to open the file both on your editor and on firebug then any saving done is reloaded automatically.
A better example, you open the file ‘hello.js’ both on your editor and firebug using the new ‘Open’ button, you edit the text from your editor and save then switch to Firebug console window and immediately the text is updated with last saved version from the editor.
VSW with Firebug support isn’t officially released but if you are interested in testing it you can download ViewSourceWith 0.9a1