title: dynamically add and process entries for an inventory (forms)
body: <p>I have this inventory setup wherein I have a quantity, a drop down for selecting a product and it's corresponding price, and total cash amount for that respective product. This is the code for the user input.</p>
  
  <pre><code>&lt;input type = 'number' name='prod_quantity' value='1'/&gt;
  &lt;?=form_dropdown('prod_selected',$prod_opts)?&gt;
  &lt;input type = 'text' name='prod_amount' disabled='disabled' onblur="updateAmount()"/&gt;
  &lt;button&gt;Add Entries&lt;/button&gt;
  </code></pre>
  
  <p>However, this only limits to 1 entry after entering the data. And surely the user wants more entries to add. How can I repeatedly add an entry one by one without affecting the whole inventory after submitting it for processing? </p>
  
  <p>NOTES:</p>
  
  <p>(A 2 dimensional array with an N x 3 would be an idea -- e.g. $_POST['inventory'] as a 2-d array)</p>