title: Google maps api : infowindow background transparent
body: <p>My website use google maps and display popup (InfoWindow) when clicking on markers.
  I don't know why and since when, but actually the popup background is transparent.</p>
  
  <p>Can anyone help me understand?</p>
  
  <p><strong>UPDATE after good answer of Dr.Molle</strong></p>
  
  <p>Wrong code :</p>
  
  <pre><code>var infoWindow = new google.maps.InfoWindow({maxWidth: '500px'}), mapsMarker, i;
  </code></pre>
  
  <p>Good code :</p>
  
  <pre><code>var infoWindow = new google.maps.InfoWindow({maxWidth: '500'}), mapsMarker, i;
  </code></pre>