Close Text Area Script?

Hello (again),

Well I've been searching google for my answer for over 3 hours, but cannot find it, so i thought I'd ask here. Does anybody know the script / code that allow a text area to have an "X" button to close it? I want to add a "announcments" in a home page message, but want members to be able to "X" it's messages out once they've read it (or just X it out). If you don't know the code, but have a term i should google, I'd appreciate that aswell.

Thankyou