title: Changing CSS Style of Element on Mobile Devices
body: <p>Javascript newbie here.</p>
  
  <p>I have an element called 'up_arrow" (picture of an up arrow). I want a script that shows the arrow on desktops but not on mobile devices. So I attempted to use the following script:</p>
  
  <pre><code>&lt;script&gt;
  if(/Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test( navigator.userAgent )){
      document.getElementById('up_arrow').style.visibility = 'hidden';
  }
  &lt;/script&gt;
  </code></pre>
  
  <p>The up arrow image shows on my computer, but it also shows on my Android phone. Can someone please explain to me what error I made in my coding?</p>
  
  <p>Thanks in advance!</p>
  
  <p><strong>EDIT</strong>:
  I have include the element 'up_arrow's code</p>
  
  <pre><code>&lt;a href="#header-wrapper"&gt;&lt;img id="up_arrow" class="uparrow" alt="uparrow" src="images/uparrow.png"&gt;&lt;/a&gt;
  </code></pre>