[pwdisswordfish9]

A bookmarklet is more or less just a JS expression that executes on command (the user's, that is). The execution model is approximately the same as for content-delivered scripts, and it's subject to the same constraints.

So, yes, if you just naively write a bookmarklet that navigates to a new page with e.g. assignment to window.location and then expect any result other than the next line of code not executing, then you're going to be disappointed. You solve this the same way you'd solve it if you were writing an ordinary Web app--implemented in JS delivered by the server with script elements on your own page. Two stupid easy solutions that immediately come to mind: use XHR/fetch instead of actual page navigation; alternatively, have the bookmarklet open up a ~postage stamp-sized window with window.open that you can use both to output visible diagnostics and to keep the crawler resident (by doing all the work in the diagnostic window's context, which uses window.opener to control the initial tab as its puppet)... etc.