title: Calculation geolocation distance returns NaN
body: <p>I am trying to work out the distance between a user and the coordinates below, I am not sure what I have done wrong, but I get the response 'NaN' (not a number)</p>
  
  <p>HTML:</p>
  
  <pre><code>&lt;h3&gt;Come visit&lt;/h3&gt;
  &lt;p&gt;You're only &lt;span class="distance"&gt; &lt;/span&gt;km away&lt;/p&gt;
  </code></pre>
  
  <p>JS File:</p>
  
  <pre><code>// Location
  if($('#content').hasClass('contact_page')) {
      var localSearch = new GlocalSearch();
      var sharp_hq = {
          lat: 53.639993,
          lng: -1.782354
      };
     // calculate the distance between me and thee
      var calculate_distance = function(location) {
          return Math.round(3959 * 1.609344 
         * Math.acos(Math.cos(0.0174532925 * location.y) 
         * Math.cos(0.0174532925 * sharp_hq.lat)
         * Math.cos((0.0174532925 * sharp_hq.lng) - (location.x * 0.0174532925))
         + Math.sin(0.0174532925 * location.y)
         * Math.sin(0.0174532925 * sharp_hq.lat)));
      };
  
      // geo location
      if(navigator.geolocation) {
          navigator.geolocation.getCurrentPosition(function(position) {
              initialLocation = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
              //display in .distance &lt;span&gt;
              $('.distance', '.location').html(calculate_distance(initialLocation));
              $('p', '.location').css({ display: 'block' });
          });
      }
  }
  </code></pre>