title: Div background image wont show on mobiles
body: <p>I have a div class with a background image set. It displays ok on pc browsers but it wont show the image on mobile browser(i have tried android and ios)</p>
  
  <p>the html</p>
  
  <pre><code>&lt;div class="wrapper"&gt;
     &lt;div class="headerdiv"&gt;
        &lt;?php include '../inc/header.php';?&gt;
     &lt;/div&gt;
     &lt;div id="wherewhen"&gt;
        &lt;div id="when"&gt;
           &lt;span class="wherewhen"&gt;WHEN IS IT?&lt;/span&gt;&lt;br /&gt; 
           &lt;span class="wherewhentext"&gt;9TH/10TH FEBUARY 2014&lt;/span&gt;
    &lt;/div&gt;
    &lt;div id="where"&gt;
           &lt;span class="wherewhen"&gt;WHERE IS IT?&lt;/span&gt;&lt;br /&gt; 
           &lt;span class="wherewhentext"&gt;HOLIDAY INN, MILTON KEYNES, ENGLAND&lt;/span&gt;
    &lt;/div&gt;
    &lt;div id="what"&gt;
           &lt;span class="wherewhen"&gt;WHAT IS IT?&lt;/span&gt;
        &lt;/div&gt;
    &lt;div id="info"&gt;
           &lt;span class="wherewhentext"&gt; 
           A BACK IN THE DAY STYLE CONVENTION 
           FOR DISENFRANCHISED ARTISTS AND TATTOO FANS FED UP 
           WITH TODAY'S COMMERCIAL CORPORATE EXPOS.
           &lt;/span&gt;
    &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="poster"&gt;
    &lt;/div&gt;
  </code></pre>
  
  <p>the css</p>
  
  <pre><code>html, body{
  margin:0; 
  padding:0;
  width:100%;
  height:100%;
  overflow:auto;
  background:#000000;
  }
  
  .wrapper{
  width:80em;
  margin: 0 auto 0 auto;
  background:#000000;
  overflow:hidden;
  }
  
  .poster{
  float:left;
  margin:-900px 0 0 910px;
  width:370px;
  min-height:600px;
  background:#ffffff url('../images/siteimages/background.png');
  }
  
  #wherewhen{
  background:#392da3;
  width:600px;
  margin:20px 20px 0 295px;
  text-shadow: 2px -2px #000000;
  
  }
  
  #where{
  float:left;
  text-align:center;
  width:20em;
  }
  
  #when{
  float:right;
  text-align:center;
  width:15em;
  }
  
  #what{
  width:20em;
  text-align:center;
  margin:0 auto 0 auto;
  }
  
  #info{
  width:30em;
  margin:0 auto 0 auto;
  }
  </code></pre>
  
  <p>Can anyone offer assistance here?</p>
  
  <p>Thanks...</p>