title: jQuery selector with sum
body: <p>I didn't know a good title for my problem, this is why I didn't search.</p>
  
  <p>My problem is the following:</p>
  
  <p>I have a HTML code, for example:</p>
  
  <pre><code>&lt;input type="text" id="product_qty_1" value="12" /&gt;
  &lt;input type="text" id="product_qty_2" value="21" /&gt;
  &lt;input type="text" id="product_qty_3" value="45" /&gt;
  </code></pre>
  
  <p>I'd like to make a sum of the values by jQuery, but this need to be automatic, because we can't know how many <code>inputs</code> are there.</p>
  
  <p>I don't know, what to do with the selector <code>input[id*="product_qty_"]</code> to get it working, and make a sum of the values!</p>
  
  <p>Thanks in advance!</p>