title: How can I remove default button class of a dataTables button?
body: <p>I am using Data table with Button. I want to show Success button rather default.
  I tried this Code</p>
  
  <pre><code>buttons: [
  {
  extend: "excel",
  className: "btn-sm btn-success",
  titleAttr: 'Export in Excel',
  text: 'Excel'
  }]
  </code></pre>
  
  <p>This code is working but this is adding btn-success class, But I want to remove the btn-default class first and then add the success class.</p>
  
  <p>Current Classes: <code>"btn btn-default buttons-excel buttons-html5 btn-sm btn-success"</code></p>
  
  <p>What I want : <code>"btn buttons-excel buttons-html5 btn-sm btn-success"</code></p>