如何修复下面这个无效的正则表达式？

Question

我正在尝试从php脚本上传文件的一个页面（imageupload.php）中检索文件名，我想在javascript函数（QandATable.php）中的另一个页面中显示它。但我不知道如何正确执行此操作，因为我一直收到无效的正则表达式标志w错误。如何修复此错误并显示从php脚本中将$_SESSION['fileImage']['name']从imageupload.php页面检索到QandATable.php中的stopUploadImage javascript函数。

下面是php脚本，它将文件上传到服务器（imageupload.php）：这是$_SESSION['fileImage']['name'] = $_FILES['fileImage']['name'];出现的位置。

    <?php

    session_start();

    $result = 0;

    if( file_exists("ImageFiles/".$_FILES['fileImage']['name'])) {
    $_SESSION['fileImage']['name'] = $_FILES['fileImage']['name'];
        $parts = explode(".",$_FILES['fileImage']['name']);
        $ext = array_pop($parts);
        $base = implode(".",$parts);
        $n = 2;

        while( file_exists("ImageFiles/".$base."_".$n.".".$ext)) $n++;
        $_FILES['fileImage']['name'] = $base."_".$n.".".$ext;

        move_uploaded_file($_FILES["fileImage"]["tmp_name"],
        "ImageFiles/" . $_FILES["fileImage"]["name"]);
        $result = 1;

    }
        else
          {
          move_uploaded_file($_FILES["fileImage"]["tmp_name"],
          "ImageFiles/" . $_FILES["fileImage"]["name"]);
          $result = 1;     

          }

    ?>

    <script language="javascript" type="text/javascript">
window.top.window.stopImageUpload(<?php echo $result;?>);
</script>

下面是我要检索$_SESSION['fileImage']['name'] = $_FILES['fileImage']['name'];的javascript代码，但是它给了我无效的正则表达式标志w错误。

     function stopImageUpload(success){

var imagename = <?php echo json_encode($_SESSION['fileImage']['name']); ?>;
              var result = '';
              if (success == 1){
    result = '<span class="msg">The file was uploaded successfully!</span><br/><br/>';
                 $('.listImage').append(imagename + '<br/>');
              }
              else {
    result = '<span class="emsg">There was an error during file upload!</span><br/><br/>';
              }

        return true;

        }