When the button is clicked multi-column filtering on the server side

$.fn.dataTableExt.afnFiltering.push(
				function (oSettings, aData, iDataIndex) {
					var txtName = document.getElementById('txtName').value;
						txtName = $.trim(txtName);
					var colunm1 = $.trim(aData[0]);
					if (txtName == "") {
						return true;
					} else if (colunm1 == txtName) {
						return true;
					}
					return false;
				}
			);
			$(function () {
				var oTable = $('#example').dataTable({
					"bFilter": true, 
					"bProcessing": true,
					"bServerSide": true,
					"sAjaxSource": "scripts/dataTable.php"
				});
			$('#send').click(function(){
					oTable.fnDraw();
				});
			})

I found that it can not filter data "txtName = document.getElementById('txtName').value;" passed to the server

what can i do ? please help me...

Is that so?

	"fnServerParams": function ( aoData ) {
                var txtName = document.getElementById('txtName').value;
		aoData.push( { "name": "more_data", "value": "txtName " } );
       }

But I do not know how to call “fnServerParams” to server.

Like this？

	$(function () {
				var oTable = $('#example').dataTable({
					"bFilter": true, 
					"bProcessing": true,
					"bServerSide": true,
					"sAjaxSource": "scripts/dataTable.php"
				});
			$('#send').click(function(){
					oTable.fnServerParams(aoData )｛
                                                   var txtName = document.getElementById('txtName').value;
		                                   aoData.push( { "name": "more_data", "value": "txtName " } );
                                          ｝
				});
       }