I was reading a book and found this...

Perhaps the best-known exception is the javascript: scheme (in earlier
years, also available under aliases such as livescript: or mocha: in Netscape brows-
ers). This scheme gives access to the JavaScript-programming engine in the
context of the currently viewed website.
When I checked the protocol livescript: still works in internet explorer 6. (Not checked in other versons/browsers yet)
I thought some of you might not be known this so sharing with you guys.
I think this might be used in bypassing some filters while attacking ???
What you guys say ?