help in modifying open new ticket page

Hi all

Modified the open.inc.php as per our organisation needs.

so that it asks

1. Department

2. again a drop down menu which has a list of categories of problem instead of subject.

Now like to have a multiple drop down menu, so that as per the value of the department, the list of dropdown menu for category of problem changes..

Pls help in doing this. I am not PHP expert..

regds

cholam2

Please help with any solution for this post.