r ‘ipv6’ to specify
an IP format. The default checks for both formats.</p>
</dd></dl>

<dl class="method">
<dt id="CI_Input::user_agent">
<code class="descname">user_agent</code><span class="sig-paren">(</span><span class="optional">[</span><em>$xss_clean = NULL</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#CI_Input::user_agent" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="