It displays a blank web page when I open it - php

Question

When I open up the web page, it just shows a blank page. Do you know why it is doing this? Could it be because of the [] in the $_SESSION? There is no javascript errors on error console and I don't php errors on screen.
Below is the javascript code where the appending occurs:
<?php
session_start();
$idx = count($_SESSION ['fileImage'] - 1);
$output = isset($_SESSION ['fileImage'][$idx]) ? $_SESSION ['fileImage'][$idx]['name'] : "";
?>
function stopImageUpload(success){
var imageNameArray = ['<?php echo $output ?>'];
var result = '';
if (success == 1){
result = '<span class="msg">The file was uploaded successfully!</span><br/><br/>';
for(var i=0;i<imageNameArray.length;i++)
{
$('.listImage').append(imageNameArray[i]+ '<br/>');
}
}
else {
result = '<span class="emsg">There was an error during file upload!</span><br/><br/>';
}
return true;
}
Below is the php script where it uploads a file which is on another page from the javascript function above:
<?php
session_start();
$result = 0;
$errors = array ();
$dirImage = "ImageFiles/";
if (isset ( $_FILES ['fileImage'] ) && $_FILES ["fileImage"] ["error"] == UPLOAD_ERR_OK) {
$fileName = $_FILES ['fileImage'] ['name'];
$fileExt = pathinfo ( $fileName, PATHINFO_EXTENSION );
$fileExt = strtolower ( $fileExt );
$fileDst = $dirImage . DIRECTORY_SEPARATOR . $fileName;
if (count ( $errors ) == 0) {
if (move_uploaded_file ( $fileTemp, $fileDst )) {
$result = 1;
}
}
}
$_SESSION ['fileImage'][] = array('name' => $_FILES ['fileImage']['name']);
?>
<script language="javascript" type="text/javascript">window.top.stopImageUpload(<?php echo $result;?>);</script>

Answer 1

$idx = count($_SESSION ['fileImage'] - 1);
should be
$idx = count($_SESSION ['fileImage']) -1 ;
var imageNameArray = new Array();
imageNameArray = <?php echo $output ?>;
should become
var imageNameArray = ['<?php echo $output ?>'];