title: Getting lengthmenu value from datatable
body: <p>I have the following option as part of:</p>
  
  <pre><code>"lengthMenu": [[10, 20, 50, 100, -1], [10, 20, 50, 100, "All"]],
  </code></pre>
  
  <p>and I'm attempting to get the value selected for lengthMenu. However, after looking through the jquery API I cannot seem to find anything to get this value after it has been changed. Any possible solutions you guys can think of?</p>