title: How to solve "implode(): Invalid arguments passed"?
body: <p>I'm trying to implode some checkbox values into a single String to store it on a Database field (as it is the only way I think I can do it), but I'm getting this error:</p>
  <pre><code>implode(): Invalid arguments passed
  </code></pre>
  <p>My HTML code is:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;input type=&quot;checkbox&quot; name=&quot;oportunitats[]&quot; value=&quot;1&quot;&gt;
  &lt;input type=&quot;checkbox&quot; name=&quot;oportunitats[]&quot; value=&quot;2&quot;&gt;
  &lt;input type=&quot;checkbox&quot; name=&quot;oportunitats[]&quot; value=&quot;3&quot;&gt;
  &lt;input type=&quot;checkbox&quot; name=&quot;oportunitats[]&quot; value=&quot;4&quot;&gt;
  </code></pre>
  <p>And my PHP looks like this:</p>
  <pre class="lang-html prettyprint-override"><code>$chk_oportunitats = implode(&quot;,&quot;,$_POST[&quot;oportunitats&quot;]);
  </code></pre>