
</tr>
</tbody>
</table>
<p>Returns the requested HTTP header value, or NULL if the requested header is not set.
Example:</p>
<div class="highlight-ci"><div class="highlight"><pre><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">output</span><span class="o">-&gt;</span><span class="na">set_content_type</span><span class="p">(</span><span class="s1">&#39;text/plain&#39;</span><span class="p">,</span> <span class="s1">&#39;UTF-8&#39;</span><span class="p">);</span>
<span class="k">ech