How to Export Multiple Row Headers in jQuery Datatables?

Question

Hi I am using jQuery Datatables 1.10. I am trying to export Datatable multiple header rows but not getting. But it is Exporting only second header row. I am using Buttons:

Answer 1

Adding to the solution that was given by Ronnie, since most of us got confused how exactly the approach works, would like to take it in a detail.

1. To get Excel button working add buttons.html5.js, dataTables.buttons.min.js, jszip.min.js.

2. For multiple row header table export, add below function in buttons.html5.js at the bottom of the document

   var _fnGetHeaders = function(dt) {
   var thRows = $(dt.header()[0]).children();
   var numRows = thRows.length;
   var matrix = [];
   
   // Iterate over each row of the header and add information to matrix.
   for ( var rowIdx = 0;  rowIdx < numRows;  rowIdx++ ) {
       var $row = $(thRows[rowIdx]);
   
       // Iterate over actual columns specified in this row.
       var $ths = $row.children("th");
       for ( var colIdx = 0;  colIdx < $ths.length;  colIdx++ )
       {
           var $th = $($ths.get(colIdx));
           var colspan = $th.attr("colspan") || 1;
           var rowspan = $th.attr("rowspan") || 1;
           var colCount = 0;
   
           // ----- add this cell's title to the matrix
           if (matrix[rowIdx] === undefined) {
               matrix[rowIdx] = [];  // create array for this row
           }
           // find 1st empty cell
           for ( var j = 0;  j < (matrix[rowIdx]).length;  j++, colCount++ ) {
               if ( matrix[rowIdx][j] === "PLACEHOLDER" ) {
                   break;
               }
           }
           var myColCount = colCount;
           matrix[rowIdx][colCount++] = $th.text();
   
           // ----- If title cell has colspan, add empty titles for extra cell width.
           for ( var j = 1;  j < colspan;  j++ ) {
               matrix[rowIdx][colCount++] = "";
           }
   
           // ----- If title cell has rowspan, add empty titles for extra cell height.
           for ( var i = 1;  i < rowspan;  i++ ) {
               var thisRow = rowIdx+i;
               if ( matrix[thisRow] === undefined ) {
                   matrix[thisRow] = [];
               }
               // First add placeholder text for any previous columns.                 
               for ( var j = (matrix[thisRow]).length;  j < myColCount;  j++ ) {
                   matrix[thisRow][j] = "PLACEHOLDER";
               }
               for ( var j = 0;  j < colspan;  j++ ) {  // and empty for my columns
                   matrix[thisRow][myColCount+j] = "";
               }
           }
       }
   }
   
   return matrix;
   };
   

3. With in the same file find DataTable.ext.buttons.excelHtml5 and replace the code block

   if(config.header){
       /*Existing code*/
   }
   

   to

   if (config.header) {
       /* ----- BEGIN changed Code ----- */
       var headerMatrix = _fnGetHeaders(dt);
       for (var rowIdx = 0; rowIdx < headerMatrix.length; rowIdx++) {
           addRow(headerMatrix[rowIdx], rowPos);
       }
       /* ----- OLD Code that is replaced: ----- */
       //addRow( data.header, rowPos );
       /* ----- END changed Code ----- */
       $('row c', rels).attr('s', '2'); // bold
   }
   

That's it. you would be able to export the multiple header rows.

And adding to the above if you want to export merged cells then below code would help you.

Add this to buttons customize function.

buttons: [
    {
        extend: 'excel',
        customize: function (xlsx) {
            //Apply styles, Center alignment of text and making it bold.
            var sSh = xlsx.xl['styles.xml'];
            var lastXfIndex = $('cellXfs xf', sSh).length - 1;

            var n1 = '';
            var s2 = '' +
                    '';

            sSh.childNodes[0].childNodes[0].innerHTML += n1;
            sSh.childNodes[0].childNodes[5].innerHTML += s2;

            var greyBoldCentered = lastXfIndex + 1;

            //Merge cells as per the table's colspan
            var sheet = xlsx.xl.worksheets['sheet1.xml'];
            var dt = $('#tblReport').DataTable();
            var frColSpan = $(dt.table().header()).find('th:nth-child(1)').prop('colspan');
            var srColSpan = $(dt.table().header()).find('th:nth-child(2)').prop('colspan');
            var columnToStart = 2;

            var mergeCells = $('mergeCells', sheet);
            mergeCells[0].appendChild(_createNode(sheet, 'mergeCell', {
                attr: {
                    ref: 'A1:' + toColumnName(frColSpan) + '1'
                }
            }));

            mergeCells.attr('count', mergeCells.attr('count') + 1);

            var columnToStart = 2;

            while (columnToStart <= frColSpan) {
                mergeCells[0].appendChild(_createNode(sheet, 'mergeCell', {
                    attr: {
                        ref: toColumnName(columnToStart) + '2:' + toColumnName((columnToStart - 1) + srColSpan) + '2'
                    }
                }));
                columnToStart = columnToStart + srColSpan;
                mergeCells.attr('count', mergeCells.attr('count') + 1);
            }

            //Text alignment to center and apply bold
            $('row:nth-child(1) c:nth-child(1)', sheet).attr('s', greyBoldCentered);
            for (i = 0; i < frColSpan; i++) {
                $('row:nth-child(2) c:nth-child(' + i + ')', sheet).attr('s', greyBoldCentered);
            }

            function _createNode(doc, nodeName, opts) {
                var tempNode = doc.createElement(nodeName);
                if (opts) {
                    if (opts.attr) {
                        $(tempNode).attr(opts.attr);
                    }
                    if (opts.children) {
                        $.each(opts.children, function (key, value) {
                            tempNode.appendChild(value);
                        });
                    }
                    if (opts.text !== null && opts.text !== undefined) {
                        tempNode.appendChild(doc.createTextNode(opts.text));
                    }
                }
                return tempNode;
            }

            //Function to fetch the cell name
            function toColumnName(num) {
                for (var ret = '', a = 1, b = 26; (num -= a) >= 0; a = b, b *= 26) {
                    ret = String.fromCharCode(parseInt((num % b) / a) + 65) + ret;
                }
                return ret;
            }
        }
    }
]