title: Making a div vertically scrollable using CSS
body: <p>This</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="" style="overflow:scroll; height:400px;"&gt;</code></pre>
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  </p>
  
  <p>gives a <code>div</code> that the user can scroll in both in horizontally and vertically. How do I change it so that the div is <em>only</em> scrollable vertically?</p>