[jQuery] Autocomplete JSON filtering searches

[sAmUrAi]

I have a JSON dataset structured as follows
{
  {
    city=>value
    area=>value
  }
  {
    city=>value
    area=>value
  }
  {
    city=>value
    area=>value
  }
  ...
  ...
  ...
}

I need two autocomplete inputs,
 - one allowing only selections of cities and
 - one allowing selection of areas of the selected city

I have about 7 cities and 47 areas.