Ajax自动完成字段：显示一个值，但使用另一个值？

I've got an autocompleter in a CakePHP app that provides a dropdown list of neighborhoods to attach to a place. I'm pulling from a table 'neighborhoods' with name and id fields. I want the user to see the name of the neighborhood, and I want the app to see the id of the neighborhood and insert it into the places table. How can I make this happen?I've got an autocompleter in a CakePHP app that