A "dropdown box" refers to a small menu that appears when you click on a specific area. It gives you options to choose from in a list format that you can select by clicking on them. Full definition
To locate the expenditure data, the user must click on the «School Statistics» link under the «Data System Management» dropdown box on the menu bar at the main page, then click on either «Quick Facts» or «Guided Inquiry» on the upper menu bar and select «District & School Info.» (cato.org)
Still, those looking for casual sex can now select the correct dropdown box, instead of only talking about sex in their profiles, and find someone just as eager to hop in the sack. (datingadvice.com)
The «Finance and Funding» option in the «Category List» dropdown box leads to all the relevant financial data. (cato.org)