How to make an auto-suggest / autocomplete address field for City and District (additional custom address attribute)?

In nC configuration > Countries > Edit Country Details --> Sub-level "States and provinces" can be managed

I added district, (custom address attribute): In configuration > Customer Settings > Address form fields > added District (additional custom address attribute)

Example:

Country: China
        --> States/provinces: Beijing
                              --> City: Beijing
                                   --> District: Haidian District


Now, I'm looking for a solution for front-end to help customer fill correct data, to displayed City and District beside Country and State/Province, that can be also drop-down or auto-suggest / autocomplete function.

Anyone having an idea, or solution for this?
Maybe someone already dev. a plugin? Or solved similar issue to auto-suggest?

Thanks for any helpful constructive feedback.