title: jQuery disable button on page by classname
body: <p>I need a function to disable this button:</p>
  
  <pre><code>&lt;button type="submit" 
          title="Place Order" 
          class="button btn-checkout" 
          onclick="review.save();"&gt;&lt;span&gt;&lt;span&gt;Place Order&lt;/span&gt;&lt;/span&gt;
  &lt;/button&gt;
  </code></pre>
  
  <p>I was thinking about calling it before the review.save in the onclick.
  Should I remove the onclick attribute and make it a click event handler and do it there?</p>
  
  <p>Some customers are pressing the button twice and getting duplicate orders and charges.
  Should I disable the submit of the form as well? How is the best way to handle this? This is a Magento One Page Checkout.</p>