Good point. Although a bookmarklet can also ignore the current site and just open a new tab, it can't embed custom JavaScript into that new tab.
But at least it can open a new tab with a full-page iframe, which was just enough for me to implement my autoreload bookmarklet. [1]
Apart from that, I believe there are meta-extensions which provide a generic way to inject JavaScript into every page. This is just one extension, but manages multiple bookmarklets (or whatever they call these snippets).
But at least it can open a new tab with a full-page iframe, which was just enough for me to implement my autoreload bookmarklet. [1]
Apart from that, I believe there are meta-extensions which provide a generic way to inject JavaScript into every page. This is just one extension, but manages multiple bookmarklets (or whatever they call these snippets).
[1] https://vog.github.io/autoreload/