Weird quirk when using [ code ] tags

I was using the [ code ] ... [ /code ] tags to illustrate a Javascript solution, and discovered if I have the string "javascript:" (That's "Javascript" as one word followed by a colon), it displays in the thread as "java script" (all lower case, two words).
The following Code tag has the following string: "This is a test of javascript: in a code tag. javascript:javascript:javascript:"

Code:

This is a test of javascript[b][/b]: in a code tag.  javascript[b][/b]:javascript[b][/b]:javascript[b][/b]:

EDIT: It's happening outside the code tags too! Click Edit on this post to see what I really typed. It wasn't "java script" followed by a colon.
EDIT 2 I'm guessing this is a feature to prevent embedding JavaScript inside a post, right?
KJP

 

Ok thanks. I was just providing sample code snippets, nothing intended to be executable from the forum page.

KJP