title: Primefaces onstart vs onclick
body: <p>What is the difference between <code>onclick</code> and <code>onstart</code>?</p>
  
  <p><strong>e.g.</strong></p>
  
  <pre><code>&lt;p:commandButton id="checkout" value="Complete Checkout" action="#{checkoutBean.checkout}" update="@form" 
      onclick="PF('blockui').block()" onstart="PF('blockui').block()" oncomplete="PF('blockui').unblock()"/&gt;
  </code></pre>