CSS Accordion Menu - Javascript help needed

[essdeepee]

Hi there,

Can someone help me with this?

I have put together an accordion menu using css, html (ul, li tags) and javascript.

I'd like the arrows on the collapsible menus should change state depending on if they're open or not. The triangle turner should point right when the content is closed and can be opened. The triangle turner should point up when the content is open and can be closed.

But I'm not sure how to replace this arrow image css using javascript.

css style to open menu: level01_top_link_subnav_open
css style to close menu: level01_top_link_subnav_close

I have attached the menu page and its associated files (see the zip file).
I'd appreciate if someone can help me with this.

Many thanks in advance.

[essdeepee]

You can view the menu here:
http://praky.com/demo/gui-prototype/...accordion.html