Neighborhood database

I am updating a neighborhood website and need a plugin which I simply don’t know how to search for. I have used a number of possible search terms without luck, and it may be something created from scratch.

Each of the homes in our neighborhood has a lot number assigned to it for recordkeeping. What I need is a tool that will allow a resident to enter their street number and, from a drop down menu, select their street. When they submit this, their lot number will be displayed next to the form (preferably without requiring a new page being loaded).

Any thoughts on how to find an existing or modifiable tool to do this, or help creating it would be appreciated.

Thanks!