Multiple category drop downs

Hi there,

I’m not a coder so please bear with me, especially if I don’t use the right terms a coder may use…

I need to have two drop down search boxes, for the parent category and child category. To explain what I need to achieve:
The first ‘search box’ will select the parent category, the second ‘search box’ will select the child data depending on the category selected in the first box.

This is for a healthtech site, so for example the first search box the user will select the main (parent category)condition e.g. diabetes, respiratory, cardiac… etc
Then the contents of the second drop down will change to display the relevant (child category) sub-condition:
So if you select diabetes in the first box, the second box gives the option of type 1, types 2 etc….
Or if you select Respiratory in the first box, the second box will let you select the relevant conditions such as asthma, bronchitis, COPD etc.

At present all the parent and child categories are under one drop down which means it will become a very long list.

The page I need help with: [log in to see the link]