title: I want to restrict textarea characters length to 150 characters, My system.xml code is below :
body: <p>I want to restrict textarea characters length to 150 characters, My system.xml code is below :</p>
  
  <pre><code>...
  &lt;orderPlaceMessage translate="label"&gt;
      &lt;label&gt;Message for order place: &lt;/label&gt;
      &lt;frontend_type&gt;textarea&lt;/frontend_type&gt;
      &lt;sort_order&gt;1&lt;/sort_order&gt;
      &lt;show_in_default&gt;1&lt;/show_in_default&gt;
      &lt;show_in_website&gt;1&lt;/show_in_website&gt;
      &lt;show_in_store&gt;1&lt;/show_in_store&gt;
  
      {how to limit character length }
  
  &lt;/orderPlaceMessage&gt;
  ...
  </code></pre>