Insertion of BB codes

[PHPstarter]

Hi, I'm pretty new to javascript, but I managed to make a simple BB Code script which allows me to paste stuff like [b.] text [/b.] (without the . )into my textarea by button.
The problem is that this will always get inserted at the bottom/last in the text field, and not where the mouse is focused.

How can I make it paste these codes where my mouse is targeted?

[acoder]

A couple of threads on the same problem:

http://bytes.com/topic/javascript/answers/633942-text-box-cursor-location

http://bytes.com/topic/javascript/answers/843989-insert-text-current-cursor-position-textarea

[PHPstarter]

Thank you, I found a solution in one of those threads.
However, as my BB codes are repasted, the original, selected text is also repasted. so it looks like this:
[b.] hello [/b.] hello
instead of:
[b.] hello [/b.]

Is there any easy way to remove the selected text from a textarea? :)

[PHPstarter]

Never mind, I solved it............. :)
Thanks