$_POST data to phpExcel

我试图使用phpExcel从html表导出数据到excel文件。我遇到的问题是，我似乎无法把数据传递给它。

我有以下的jquery代码，它运行在一个按钮按下得到的数据表，并将其发布到php代码。

导出数据jquery

function storeTblValues()
{
var tableData = new Array();
$('#LogsTable tr').each(function(row, tr) 
{
    if(row == 0) //Table Headers
    {
        tableData[row] = 
        {            
            "LogDate" : $(tr).find('th:eq(0)').text(),
            "LogType" : $(tr).find('th:eq(1)').text(),
            "StartTime" : $(tr).find('th:eq(2)').text(),
            "FinishTime" : $(tr).find('th:eq(3)').text(),
            "Duration" : $(tr).find('th:eq(4)').text()
        } 
    }
    else //Table data
    {
        tableData[row] = 
        {  
        "LogDate" : $(tr).find('td:eq(0)').text(),
        "LogType" : $(tr).find('td:eq(1)').text(),
        "StartTime" : $(tr).find('td:eq(2)').text(),
        "FinishTime" : $(tr).find('td:eq(3)').text(),
        "Duration" : $(tr).find('td:eq(4)').text(),
        }            
    }
});
return tableData;
}
function exportToExcel()
{      
    var tableData;        
    tableData = $.toJSON(storeTblValues());
    var tmp = "pTableData=" + tableData;   
    $.ajax({
        type: 'POST',
        url: 'create_export_files.php',
        data : tmp,    
        success : function(data)
        {
            window.location = 'create_export_files.php';        
        }
    });    
}

接收数据的php文件的顶部位Create_export_files.php

$tableData = "";
if (isset($_POST["pTableData"]))
{
    $tableData = $_POST["pTableData"];
    $tableData = json_decode($tableData, TRUE);
}
else 
{
    $tableData = "empty";
}

generateExcel($tableData);
function generateExcel($tableData)
{
    /** Include PHPExcel */
    require_once dirname(__FILE__) . '/../Classes/PHPExcel.php';
    // Create new PHPExcel object
    $objPHPExcel = new PHPExcel();
        // Add some data
$objPHPExcel->setActiveSheetIndex(0)
            ->setCellValue('A1', 'hello')
            ->setCellValue('B2', 'world!')
            ->setCellValue('C1', 'Hello')
            ->setCellValue('D2', 'world!');
// Rename worksheet
$objPHPExcel->getActiveSheet()->setTitle('Simple');

// Set active sheet index to the first sheet, so Excel opens this as the    first sheet
$objPHPExcel->setActiveSheetIndex(0);
$filename = 'export '.date('d-m-Y h:i:a').'.xlsx';

// Redirect output to a client’s web browser (Excel2007)
header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
header('Content-Disposition: attachment;filename="'.$filename.'"');
header('Cache-Control: max-age=0');
// If you're serving to IE 9, then the following may be needed
header('Cache-Control: max-age=1');
// If you're serving to IE over SSL, then the following may be needed
header ('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); // Date in the past
header ('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT'); // always modified
header ('Cache-Control: cache, must-revalidate'); // HTTP/1.1
header ('Pragma: public'); // HTTP/1.0
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
$objWriter->save('php://output');
}

我似乎总是进入语句的else部分。我哪里做错了?

如果我移除pTableData周围的isset位，则文件被创建但被损坏。在notepad++中打开，可以看到pTableData是undefined。这是因为php文件再次运行以进行文件下载吗?