title: Only submit 'relevant' parts of HTML form
body: <p>Apologies if it's a stupid but it's been a long day.
  So my form look something like this...</p>
  
  <pre><code>&lt;form action="/basket.php" method="get"&gt;
  .co.uk
  &lt;select name="years"&gt;
  &lt;option value="1"&gt;1 year&lt;/option&gt;
  &lt;option value="2"&gt;2 years&lt;/option&gt;
  &lt;option value="3"&gt;3 years&lt;/option&gt;
  &lt;option value="4"&gt;4 years&lt;/option&gt;
  &lt;option value="5"&gt;5 years&lt;/option&gt;
  &lt;/select&gt;
  &lt;input type="checkbox" name="url" value=".co.uk"&gt;
  &lt;br&gt;
  .com
  &lt;select name="years"&gt;
  &lt;option value="1"&gt;1 year&lt;/option&gt;
  &lt;option value="2"&gt;2 years&lt;/option&gt;
  &lt;option value="3"&gt;3 years&lt;/option&gt;
  &lt;option value="4"&gt;4 years&lt;/option&gt;
  &lt;option value="5"&gt;5 years&lt;/option&gt;
  &lt;/select&gt;
  &lt;input type="checkbox" name="url" value=".com"&gt;
  &lt;button type="submit"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Let say I only ticked the <code>.com</code> parameter and changed the years to 3 years..
  I would currently get the URL as follows:</p>
  
  <pre><code>/basket.php?years=1&amp;url=.com&amp;years=3
  </code></pre>
  
  <p>What I would like is...</p>
  
  <pre><code>/basket.php?url=.com&amp;years=3
  </code></pre>
  
  <p>The actually form contains more choices but I only want to submit the 'lines' that have the final checkbox ticked.</p>
  
  <p>Hope this make sense! Many thanks in advance.</p>