When using developer tool, it is ok to refer to bookmark id=10000 .
But when there are N _concurrent_ users (same document, in same server, at the same time), should all use id=10000 ? They would be over-writing each other's bookmarks .
You could try a "temporary bookmark" for each session, ex "10000 + random()" . This is little bit safer, but still not bullet proof if there are enough concurrent users.