/cw/ uses js chunks and produces JSON chunks in the HTML elements. It also uses Transcend (
https://transcend.io) for the newer UI.
Try something like this (you can put it in a bookmarklet with javascript:alert if your browser supports it):
document.body.innerHTML.match(/creator\\":{\\"data\\":{\\"id\\":\\"(\d+)\\",\\"type\\"\:\\"user/)[1]
You can shorten the regex some more or even use a completely different approach, just remember you need that first match (the creator id in the data part) from the chunked JSON.