title: Using JavaScript to change background-image in IE
body: <p>I am very new to JavaScript. Following line works for FF and Chrome, but not for IE 11:</p>
  
  <pre><code>var header = document.getElementsByTagName("header").item(0);       
  header.style.backgroundImage = "url('./images/banner1.png'), url('./images/banner2.png')";
  </code></pre>
  
  <p>Any idea why not?</p>
  
  <p>Thanks!</p>