title: How to filter Google Maps markers in one array with select?
body: <p>I have a google maps implemented in my site with one array, like so:</p>
  <pre><code>var gmarkers1 = [];
  var markers1 = [];
  
  markers1 = [
  ['0', 'Title', 52.4357808, 4.991315699999973],
  ['1', 'Title', 52.4357808, 4.991315699999973],
  ['2', 'Title', 52.4555687, 5.039231599999994],
  ];
  </code></pre>
  <p>In this example there are 3 markers, but in reality there are a lot more. For my purpose, this is the only way to do it (one array).</p>
  <p>Question: I want to be able to filter inside this array with a selectbox. So a user selects &quot;car&quot; from a select and Google Maps only shows the markers with a property (?) &quot;car&quot;.</p>
  <p>The Markers are shown like this:</p>
  <pre><code>for (i = 0; i &lt; markers1.length; i++) {
      var category;
      var pos = new google.maps.LatLng(markers1[i][2], markers1[i][3]);
      var content = markers1[i][1];
      bounds.extend(pos);
      marker1 = new google.maps.Marker({
          position: pos,
          map: map,
          icon: image1
      });
  
      gmarkers1.push(marker1);
      // [START]-Event listener to center view and go to position
      google.maps.event.addListener(marker1, 'click', (function(marker1, content) {
          return function() {
            console.log('Gmarker 1 gets pushed')
              infowindow.setContent(content);
              infowindow.open(map, marker1);
              map.panTo(this.getPosition());
              map.setZoom(15);
          }
      })(marker1, content));
  }
  </code></pre>