County selector example

<!DOCTYPE html>
<html>
  <head>
    <title>County Selector</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <link rel="shortcut icon" href="https://cartodb.com/assets/favicon.ico" />
    <style>
      html, body, #map {
        height: 100%;
        padding: 0;
        margin: 0;
      }
    </style>
    <link rel="stylesheet" href="https://libs.cartocdn.com/cartodb.js/v3/themes/css/cartodb.css" />
  </head>
  <body>
    <div id="map"></div>
    
    
    <script src="https://libs.cartocdn.com/cartodb.js/v3/cartodb.js"></script>

// Add a baselayer to the map
        L.tileLayer('https://{s}.api.cartocdn.com/base-light-nolabels/{z}/{x}/{y}.png').addTo(map);

// Get the 'county' variable from our GET parameters
        var c = getQueryVariable('county');

// Create our data layer using our CartoDB Visualization
        cartodb.createLayer(map, 'https://andrew.cartodb.com/api/v2/viz/7fff1080-f64b-11e3-82d4-0e230854a1cb/viz.json',{
          sql: "SELECT *, true as highlight FROM us_counties_4"
        })
         .addTo(map)
         .on('done', function(layer) {

layer.getSubLayer(0).setSQL("SELECT *, name ilike '"+c+"' as highlight FROM us_counties_4 ORDER BY highlight ASC");

// After the layer has been added to the map, let's do stuff

// If county existed, do stuff
            if(c){
              // Query our CartoDB table to see if we find the County
              // This could be improved if we also required a state
              var sql = cartodb.SQL({ user: 'andrew' });
              sql.execute("select st_x(st_centroid(the_geom)) lon, st_y(st_centroid(the_geom)) lat from us_counties_4 where name ilike '" + c + "'").done(function(data) {
                // Check if there are results
                if(data.rows.length > 0){
                  map.setView([data.rows[0].lat,data.rows[0].lon], 9, {animate: true})
                }
              })
              console.log(c);
            }
        }).on('error', function() {
          cartodb.log.log("some error occurred");
        });
      }
      function getQueryVariable(variable) {
          var query = window.location.search.substring(1);
          var vars = query.split('&');
          for (var i = 0; i < vars.length; i++) {
              var pair = vars[i].split('=');
              if (decodeURIComponent(pair[0]) == variable) {
                  return decodeURIComponent(pair[1]);
              }
          }
          console.log('Query variable %s not found', variable);
      }
      // you could use $(window).load(main);
      window.onload = main;
    </script>
  </body>
</html>

Modified http://libs.cartocdn.com/cartodb.js/v3/cartodb.js to a secure url

https://libs.cartocdn.com/cartodb.js/v3/cartodb.js