Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Html.php
public function generateSheetData()
    {
        // Spreadsheet object known?
        if ($this->spreadsheet === null) {
            throw new WriterException('Internal Spreadsheet object not set to an instance of an object.');
        }

        // Ensure that Spans have been calculated?
        if ($this->sheetIndex !== null || !$this->spansAreCalculated) {
            $this->calculateSpans();
        }

        // Fetch sheets
        $sheets = [];
        if ($this->sheetIndex === null) {
            $sheets = $this->spreadsheet->getAllSheets();
        } else {
            $sheets[] = $this->spreadsheet->getSheet($this->sheetIndex);
        }

        // Construct HTML
        $html = '';

        // Loop all sheets
        $sheetId = 0;
        foreach ($sheets as $sheet) {
            // Write table header
            $html .= $this->generateTableHeader($sheet);

            // Get worksheet dimension
            $dimension = explode(':', $sheet->calculateWorksheetDimension());
            $dimension[0] = Coordinate::coordinateFromString($dimension[0]);
            $dimension[0][0] = Coordinate::columnIndexFromString($dimension[0][0]);
            $dimension[1] = Coordinate::coordinateFromString($dimension[1]);
            $dimension[1][0] = Coordinate::columnIndexFromString($dimension[1][0]);

            // row min,max
            $rowMin = $dimension[0][1];
            $rowMax = $dimension[1][1];

            // calculate start of <tbody>, <thead>
            $tbodyStart = $rowMin;
            $theadStart = $theadEnd = 0; // default: no <thead>    no </thead>
            if ($sheet->getPageSetup()->isRowsToRepeatAtTopSet()) {
                $rowsToRepeatAtTop = $sheet->getPageSetup()->getRowsToRepeatAtTop();

                // we can only support repeating rows that start at top row
                if ($rowsToRepeatAtTop[0] == 1) {
                    $theadStart = $rowsToRepeatAtTop[0];
                    $theadEnd = $rowsToRepeatAtTop[1];
                    $tbodyStart = $rowsToRepeatAtTop[1] + 1;
                }
            }

            // Loop through cells
            $row = $rowMin - 1;
            while ($row++ < $rowMax) {
                // <thead> ?
                if ($row == $theadStart) {
                    $html .= '        <thead>' . PHP_EOL;
                    $cellType = 'th';
                }

                // <tbody> ?
                if ($row == $tbodyStart) {
                    $html .= '        <tbody>' . PHP_EOL;
                    $cellType = 'td';
                }

                // Write row if there are HTML table cells in it
                if (!isset($this->isSpannedRow[$sheet->getParent()->getIndex($sheet)][$row])) {
                    // Start a new rowData
                    $rowData = [];
                    // Loop through columns
                    $column = $dimension[0][0];
                    while ($column <= $dimension[1][0]) {
                        // Cell exists?
                        if ($sheet->cellExistsByColumnAndRow($column, $row)) {
                            $rowData[$column] = Coordinate::stringFromColumnIndex($column) . $row;
                        } else {
                            $rowData[$column] = '';
                        }
                        ++$column;
                    }
                    $html .= $this->generateRow($sheet, $rowData, $row - 1, $cellType);
                }

                // </thead> ?
                if ($row == $theadEnd) {
                    $html .= '        </thead>' . PHP_EOL;
                }
            }
            $html .= $this->extendRowsForChartsAndImages($sheet, $row);

            // Close table body.
            $html .= '        </tbody>' . PHP_EOL;

            // Write table footer
            $html .= $this->generateTableFooter();

            // Writing PDF?
            if ($this->isPdf) {
                if ($this->sheetIndex === null && $sheetId + 1 < $this->spreadsheet->getSheetCount()) {
                    $html .= '<div style="page-break-before:always" />';
                }
            }

            // Next sheet
            ++$sheetId;
        }

        return $html;
    }
public function generateSheetData()
    {
        // Spreadsheet object known?
        if ($this->spreadsheet === null) {
            throw new WriterException('Internal Spreadsheet object not set to an instance of an object.');
        }

        // Ensure that Spans have been calculated?
        if ($this->sheetIndex !== null || !$this->spansAreCalculated) {
            $this->calculateSpans();
        }

        // Fetch sheets
        $sheets = [];
        if ($this->sheetIndex === null) {
            $sheets = $this->spreadsheet->getAllSheets();
        } else {
            $sheets[] = $this->spreadsheet->getSheet($this->sheetIndex);
        }

        // Construct HTML
        $html = '';

        // Loop all sheets
        $sheetId = 0;
        foreach ($sheets as $sheet) {
            // Write table header
            $html .= $this->generateTableHeader($sheet);

            // Get worksheet dimension
            $dimension = explode(':', $sheet->calculateWorksheetDimension());
            $dimension[0] = Coordinate::coordinateFromString($dimension[0]);
            $dimension[0][0] = Coordinate::columnIndexFromString($dimension[0][0]);
            $dimension[1] = Coordinate::coordinateFromString($dimension[1]);
            $dimension[1][0] = Coordinate::columnIndexFromString($dimension[1][0]);

            // row min,max
            $rowMin = $dimension[0][1];
            $rowMax = $dimension[1][1];

            // calculate start of <tbody>, <thead>
            $tbodyStart = $rowMin;
            $theadStart = $theadEnd = 0; // default: no <thead>    no </thead>
            if ($sheet->getPageSetup()->isRowsToRepeatAtTopSet()) {
                $rowsToRepeatAtTop = $sheet->getPageSetup()->getRowsToRepeatAtTop();

                // we can only support repeating rows that start at top row
                if ($rowsToRepeatAtTop[0] == 1) {
                    $theadStart = $rowsToRepeatAtTop[0];
                    $theadEnd = $rowsToRepeatAtTop[1];
                    $tbodyStart = $rowsToRepeatAtTop[1] + 1;
                }
            }

            // Loop through cells
            $row = $rowMin - 1;
            while ($row++ < $rowMax) {
                // <thead> ?
                if ($row == $theadStart) {
                    $html .= '        <thead>' . PHP_EOL;
                    $cellType = 'th';
                }

                // <tbody> ?
                if ($row == $tbodyStart) {
                    $html .= '        <tbody>' . PHP_EOL;
                    $cellType = 'td';
                }

                // Write row if there are HTML table cells in it
                if (!isset($this->isSpannedRow[$sheet->getParent()->getIndex($sheet)][$row])) {
                    // Start a new rowData
                    $rowData = [];
                    // Loop through columns
                    $column = $dimension[0][0];
                    while ($column <= $dimension[1][0]) {
                        // Cell exists?
                        if ($sheet->cellExistsByColumnAndRow($column, $row)) {
                            $rowData[$column] = Coordinate::stringFromColumnIndex($column) . $row;
                        } else {
                            $rowData[$column] = '';
                        }
                        ++$column;
                    }
                    $html .= $this->generateRow($sheet, $rowData, $row - 1, $cellType);
                }

                // </thead> ?
                if ($row == $theadEnd) {
                    $html .= '        </thead>' . PHP_EOL;
                }
            }
            $html .= $this->extendRowsForChartsAndImages($sheet, $row);

            // Close table body.
            $html .= '        </tbody>' . PHP_EOL;

            // Write table footer
            $html .= $this->generateTableFooter();

            // Writing PDF?
            if ($this->isPdf) {
                if ($this->sheetIndex === null && $sheetId + 1 < $this->spreadsheet->getSheetCount()) {
                    $html .= '<div style="page-break-before:always" />';
                }
            }

            // Next sheet
            ++$sheetId;
        }

        return $html;
    }
Generate sheet data.

@throws WriterException

@return string