DataTables plug-in for displaying sort priorities in each sorted column header

example.js

$('#example').dataTable().fnSortPriorities();

plugin.js

$.fn.dataTableExt.oApi.fnSortPriorities = function(oSettings) {
  var $this = $(this);

  $this.find('> thead tr th').each(function(i, v) {
    v.innerHTML += '<div class="dataTable-sort-priority"></div>';
  });

  function checkSort(sorts) {
    var $priorities = $this.find('> thead tr th div.dataTable-sort-priority');
    $priorities.html('');
    if (sorts && sorts.length > 1) {
      for (var i=0,len=sorts.length; i<len; ++i)
        $priorities[sorts[i][0]].innerHTML = (i + 1);
    }
  }

  $this.on('sort', function(ev, oSettings) {
    checkSort(oSettings.aaSorting);
  });

  // Check for initial multisort
  checkSort(oSettings.aaSorting);
};

style.css

table thead tr th div.dataTable-sort-priority {
  float: right;
  font-size: 9px;
  padding-right: 5px;
}