title: get value of select option and assign it to url parameter directly
body: <p>i have this code:</p>
  
  <pre><code>&lt;li class="list-group-item"&gt;&lt;i class="fa fa-check"&gt;&lt;/i&gt; Selecciona el periodo: &lt;select name="period" id="p2" class="input-block-level"&gt;&lt;option value="0" selected&gt;Mensual&lt;/option&gt; 
    &lt;option value="1"&gt;Semestral&lt;/option&gt;
    &lt;option value="2"&gt;Anual&lt;/option&gt;&lt;/select&gt;&lt;/li&gt;
  &lt;a class="btn btn-lg btn-block btn-danger" href="/modify_cart?option=add_item&amp;item_id='.$resultado2['id'].'&amp;period=" &gt;Comprar ahora!&lt;/a&gt;
  </code></pre>
  
  <p>i need to add the value of the selected option to the url link</p>
  
  <pre><code>/modify_cart?option=add_item&amp;item_id='.$resultado2['id'].'&amp;period=(the value)
  </code></pre>
  
  <p>Is it possible?</p>