I have some attributes set up using a checkbox. I want to set a limit on how many items can be selected.

For example:

Select Two Items (option name)
- Item 1
- Item 2
- Item 3
- Item 4

I have all the attributes set up fine, I want to limit the customer to only selecting two items. I couldn't find any threads referencing this or if there was already module or some java code possibly that have already been done for this.

Any help would be much appreciated. I'm using the newest version of Zen Cart.

Thanks in advance