Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Html.php
public function save($pFilename)
    {
        // garbage collect
        $this->spreadsheet->garbageCollect();

        $saveDebugLog = Calculation::getInstance($this->spreadsheet)->getDebugLog()->getWriteDebugLog();
        Calculation::getInstance($this->spreadsheet)->getDebugLog()->setWriteDebugLog(false);
        $saveArrayReturnType = Calculation::getArrayReturnType();
        Calculation::setArrayReturnType(Calculation::RETURN_ARRAY_AS_VALUE);

        // Build CSS
        $this->buildCSS(!$this->useInlineCss);

        // Open file
        $fileHandle = fopen($pFilename, 'wb+');
        if ($fileHandle === false) {
            throw new WriterException("Could not open file $pFilename for writing.");
        }

        // Write headers
        fwrite($fileHandle, $this->generateHTMLHeader(!$this->useInlineCss));

        // Write navigation (tabs)
        if ((!$this->isPdf) && ($this->generateSheetNavigationBlock)) {
            fwrite($fileHandle, $this->generateNavigation());
        }

        // Write data
        fwrite($fileHandle, $this->generateSheetData());

        // Write footer
        fwrite($fileHandle, $this->generateHTMLFooter());

        // Close file
        fclose($fileHandle);

        Calculation::setArrayReturnType($saveArrayReturnType);
        Calculation::getInstance($this->spreadsheet)->getDebugLog()->setWriteDebugLog($saveDebugLog);
    }
public function save($pFilename)
    {
        // garbage collect
        $this->spreadsheet->garbageCollect();

        $saveDebugLog = Calculation::getInstance($this->spreadsheet)->getDebugLog()->getWriteDebugLog();
        Calculation::getInstance($this->spreadsheet)->getDebugLog()->setWriteDebugLog(false);
        $saveArrayReturnType = Calculation::getArrayReturnType();
        Calculation::setArrayReturnType(Calculation::RETURN_ARRAY_AS_VALUE);

        // Build CSS
        $this->buildCSS(!$this->useInlineCss);

        // Open file
        $fileHandle = fopen($pFilename, 'wb+');
        if ($fileHandle === false) {
            throw new WriterException("Could not open file $pFilename for writing.");
        }

        // Write headers
        fwrite($fileHandle, $this->generateHTMLHeader(!$this->useInlineCss));

        // Write navigation (tabs)
        if ((!$this->isPdf) && ($this->generateSheetNavigationBlock)) {
            fwrite($fileHandle, $this->generateNavigation());
        }

        // Write data
        fwrite($fileHandle, $this->generateSheetData());

        // Write footer
        fwrite($fileHandle, $this->generateHTMLFooter());

        // Close file
        fclose($fileHandle);

        Calculation::setArrayReturnType($saveArrayReturnType);
        Calculation::getInstance($this->spreadsheet)->getDebugLog()->setWriteDebugLog($saveDebugLog);
    }
Save Spreadsheet to file.

@param string $pFilename

@throws WriterException