title: What is the meaning of "h" in "<%=h [ ...] %>"?
body: <p>When I generate a default scaffold, the display tags on show.html.erb have</p>
  
  <pre><code>&lt;%=h @broker.name %&gt;
  </code></pre>
  
  <p>I know the difference between <code>&lt;%</code> and <code>&lt;%=</code>.  What's the "h" do?</p>