There are browser plugins that let you edit <textarea> elements in your $EDITOR. I use "It's all text!" in Firefox for this purpose and it works well; the work

There are browser plugins that let you edit <textarea> elements in your $EDITOR. I use "It's all text!" in Firefox for this purpose and it works well; the workflow is pretty simple: focus in textarea, hotkey to switch to vim, save & close buffer to switch back to the browser. (not affiliated, just a user). You do of course lose rich text formatting.