One way would be to change the input type of the filter to "search" - then HTML5 browsers will automatically show a clear widget. However, you'd have to press return after clicking it, so I wanted a one-click solution.
Here's what I came up with. It works with DataTables 1.9.
// Setup DataTable Defaults $.extend( $.fn.dataTable.defaults, { fnInitComplete: function(oSettings, json) { // Add "Clear Filter" button to Filter var btnClear = $('<button class="btnClearDataTableFilter">CLEAR</button>'); btnClear.appendTo($('#' + oSettings.sTableId).parents('.dataTables_wrapper').find('.dataTables_filter')); $('#' + oSettings.sTableId + '_wrapper .btnClearDataTableFilter').click(function () { $('#' + oSettings.sTableId).dataTable().fnFilter(''); }); } });