title: Hide element by class in pure Javascript
body: <p>I have tried the following code, but it <a href="http://jsfiddle.net/rb7bn/207/" rel="noreferrer">doesn't work</a>. Any idea where I have gone wrong?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>document.getElementsByClassName('appBanner').style.visibility='hidden';</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="appBanner"&gt;appbanner&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>Using jQuery or changing the HTML is not possible as I am using <code>[self-&gt;webView stringByEvaluatingJavaScriptFromString:@""];</code> in Objective-C.</p>