Put this code into a script section into a common HTML head include file:

$(document).ready(function() {

  $('table').each(function() {
    var $table = $(this);

    var $button = $("<button type='button'>");
    $button.text("Export to spreadsheet");
    $button.insertAfter($table);

    $button.click(function() {
      var csv = $table.table2CSV({delivery:'value'});
      window.location.href = 'data:text/csv;charset=UTF-8,'
                            + encodeURIComponent(csv);
    });
  });
})

Note:

• Requires JQuery and table2CSV (i.e. put script references before the script above)
• “table” selector is a JQuery selector and can be adjusted to suit your needs
• Only works in browsers with full “Data URI” support (Firefox, Chrome, Opera) but not in IE (which only supports Date URIs for embedding binary image data into a page)
• For full browser compatibility you would have to use a slightly different approach that requires a server side script (e.g. a Java Servlet) to “echo” the CSV. Maybe I will blog about that in another post.

The JQuery DataTables plugin supports state saving for column filters. But it does not automatically set the column filter values to the saved values when the user navigates to a page that has saved filter state.

I saw the code suggested here and cleaned it up a little (for example, using the oSettings parameter of the fnInitComplete function).

$(document).ready(function() {

        var oTable = $('#REPLACE_THIS_WITH_TABLE_ID').dataTable({
            "bStateSave": true,
            "fnInitComplete": function(oSettings, json) {
                var cols = oSettings.aoPreSearchCols;
                for (var i = 0; i < cols.length; i++) {
                    var value = cols[i].sSearch;
                    if (value.length > 0) {
                        $("tfoot input")[i].value = value;
                    }
                }
            }
        });

        $("tfoot input").keyup(function () {
            oTable.fnFilter(this.value, $("tfoot input").index(this));
        });
    });

Please note that I completely removed all code that supported initial display texts in the filter fields (because I don’t use that).