title: Cannot read property 'addEventListener' of null Error, not sure why
body: <p>Whenever I hover over the image it does not enlarge and gives an error. </p>
  
  <p>HTML and Javascript code(these are two separate files):</p>
  
  <pre><code>var banner = document.getElementById("banner");
  
  function enlargePic(){
  banner.style.width = '800px';
  banner.style.height  = '300px';
  }
  
  function normalPic(){
  banner.style.width = '500px';
  banner.style.height  = '200px';
  }
  
  
  banner.addEventListener("mouseover", enlargePic, false); 
  
  banner.addEventListener("mouseout", normalPic, false); 
  
  &lt;div id="designs"&gt;
  &lt;a id="designs"&gt;&lt;/a&gt;
  &lt;h1&gt;DESIGNS.&lt;/h1&gt; 
  &lt;table&gt;
  &lt;tr&gt;
  &lt;td&gt;&lt;img src="banner2.jpg" id="banner"&gt;&lt;/td&gt;
  &lt;/tr&gt;
  &lt;/table&gt;
  &lt;/div&gt;
  </code></pre>