Different Actions In MSIE And FF - Each Section Opens When Clicked On

In the attached code, I get no errors running in either the MSIE or FF browsers. BUT, the actions are different. I'm trying to figure out why.

[Code]...

It works as designed and intended in FF browser:

1. Each section opens when clicked on, and
2. Other sections close when a section is chosen, and
3. Same section closes when clicked in succession. (same for both)

In the MSIE browser, it works as this:

1. Each section opens when clicked on, but
2. Other sections open also when chosen and first selection stays open and
3. Same section closes when clicked in succession. (same for both)

Any reason for this in MSIE and FF browsers for #1 and #2 above? how to make both scripts work the same in both browsers?