title: change form action dynamically?
body: <p>I think this question has been asked a few times and I did find a few on google too. </p>
  
  <p>However I am not trying to change the whole form action. I just need to change it partially. </p>
  
  <p>Here is what I mean:</p>
  
  <p>I have the following form:</p>
  
  <pre><code>    &lt;form action="order.php?add=&lt;?php echo $product_name; ?&gt;&amp;amp;price=&lt;?php echo $price; ?&gt;&amp;amp;qty=1" method="post"&gt;
          &lt;input type="text" name="qty" id="qty" class="qty"  size="12"   /&gt;
          &lt;input type="submit" class="button2" name="buttonadd" id="button" value="Add to cart" /&gt;
     &lt;/form&gt;
  </code></pre>
  
  <p>what I need to do is to change the <code>qty=1</code> in the form action so it reflects the <code>&lt;input type="text" name="qty" id="qty" class="qty"  size="12"   /&gt;</code> value!</p>
  
  <p>How can I achieve this?</p>