I imagine there is a name for what I am trying to accomplish, but I don't know of it, so I apologize if I confuse anyone with what i'm looking to do:

I have a particular MySQL table that lists from a large table of businesses. Inside of the table with the businesses, I have a city field.

It is to the point that performance is becoming an issue within a HTML form. Can I modify my forms to have a city drop down menu, then once a user selects a city, a list of businesses that matches that city will show up in a second drop down for the user to choose? I imagine jQuery might do the trick, but if there is another way, or if anyone has a jQuery example, I would appreciate it!