title: Form submission with a ?key=val query string already in the action attribute ignores that query string
body: <p>So I'm trying to submit a page to itself while retaining the current query string of the page.</p>
  
  <p>So the page is <code>sb.local/sb/cat.php?brandcode=JM&amp;t=cat_items</code> I pull off the query string and stick it back into the html form to preserve the parameters.  This is the resulting form:</p>
  
  <pre><code>&lt;form id="brand-select" method="get" action="?brandcode=JM&amp;t=cat_items" name="brand-select"&gt;
  Brand:
  &lt;select id="brandcode" style="width:207px" tabindex="3" name="brandcode" required=""&gt;
  &lt;option value=""&gt;&lt;/option&gt;
  &lt;option class="brand-option" value="AX" data-brandid="110"&gt; Aetrex &lt;/option&gt;
  &lt;option class="brand-option" value="AL" data-brandid="12"&gt; Alden &lt;/option&gt;
  &lt;option class="brand-option" value="ETC" data-brandid="11"&gt; Etc &lt;/option&gt;
  &lt;/select&gt;
  &lt;input type="submit" value="go"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>When I submit the form by choosing the dropdown for Aetrex (value AX), however, it goes to a url of:</p>
  
  <p><code>sb.local/sb/cat.php?brandcode=AX</code>
  in other words, it cuts out the "t=cat_items" that is in the action.  It also cuts out the "brandcode=JM" but I would almost expect that since they're duplicates.</p>
  
  <p>That's not what I expected, I expected that if there is a query string in the action attribute, it would append form values to that query string (e.g. <code>sb.local/sb/cat.php?brandcode=JM&amp;t=cat_items&amp;brandcode=AX</code>.  Instead it seems to be replacing the query string entirely with only those elements that are in the form.</p>
  
  <p>Is the form action attribute not usable for storing query parameters, only more basic url info?  </p>
  
  <p><strong>Edit:</strong>  Note that I can work around this by parsing every parameter and then putting each parameter into its own hidden field manually, except for any parameters that I want to allow to change, I was just hoping that there was some kind of simpler way.<br>
  I tested with a non-conflicting query string and that was replaced in whole even when there wasn't a conflict (in Firefox), so based on that it seems that query strings are useless in the action attribute of get forms? Or am I missing something.  </p>