How to query my DB with with javascript?

I have a page which allows users to search for their locations using the google maps API, and I want to be able to search for places I have stored in my DB that are close to the searched location.

So how can I query the DB on the fly and have the google map update?

here is my code for geocoding thus far:

    function codeAddress(address) {

      geocoder.geocode( { 'address': address}, function(results, status) {
        if (status == google.maps.GeocoderStatus.OK) {
          latLng = results[0].geometry.location;
          map.setCenter(results[0].geometry.location);
          result=results[0].address_components;
          var info=[];
          for(var i=0;i<result.length;++i)
            {
                if(result[i].types[0]=="administrative_area_level_1"){state = i.long_name; }
                if(result[i].types[0]=="locality"){city = i.long_name;}
            } 
        ......

So how can I take those city and state variables and pass them to my controller to look for records?

EDIT - Im not using jquery on this page at all, the google maps API is plain ol' javascript.

I have zero AJAX knowledge, and very very little javascript knowledge.

So like, if I have the following variables: var state ="MD" and var City = "Bethesda"

and my controller so far is:

  def shops
      @maps = Map.where("state LIKE ?", "%#{params[:state]}%" and "city LIKE ?", "%#{params[:city]}%")
  end

And then I have to get that array back and loop through it all to display it.

And I have no idea how to do this, Ive seen numerous AJAX examples with rails but so far nothing has been particularly helpful..