I wanted to make a bookmarklet that changes the current YouTube URL to its equivalent on listenonrepeat.com, so I could repeat the video. I have a bookmark in my bookmarks bar with the following javascript:
javascript:window.location=window.location.href.replace("youtube","listenonrepeat");
Yet it won't change it unless I copy and paste it into the URL bar. Safari 6.
Can be seen here: http://christianselig.com/youtubefix.html