pass a hidden input value to php - php

Question

i found this code to upload profile image,
http://www.phpdevblog.eu/2011-04/combined/jquery-ajax-and-php-based-profile-image-upload-without-reloading-the-page.html#comments
everything are fine. but i want to set a name file = user_id
how i pass the input hidden user_id value to the php upload file process?
var uploadURL = "processupload.php";
$(document).ready(function(){
$('a#uploadFile').file();
$('a#delete').click(function(){
$('input#profileImageFile').val("");
$('img#profileImage').attr("src","/images/styles/profileBlank.jpg");
$('div#messageBox').html("Image deleted !");
$('div#messageBox').attr("class","success");
$('a#delete').hide();
});
$('input#uploadFile').file().choose(function(e, input) {
input.upload(uploadURL, function(res) {
if (res=="invalid"){
$('div#messageBox').attr("class","error");
$('div#messageBox').html("Invalid extension !");
}else{
$('div#messageBox').attr("class","success");
$('div#messageBox').html("Imagen cargada !");
$('img#profileImage').attr("src","/images/avatars/"+res);
$('input#profileImageFile').val(res);
$('a#delete').show();
$(this).remove();
}
}, '');
});
});
html
<div class="imageContainer">
<img alt="" src="/images/avatars/<?php echo $row_rs_user['user_image']; ?>" width="150" height="150" id="profileImage">
<img alt="" src="/images/styles/upload.jpg">
<img alt="" src="/images/styles/delete.jpg">
<input type="hidden" name="user_id" value="<?php echo $row_rs_user['user_id']; ?>">
<div id="messageBox"></div>
</div>
PHP upload process
if(isset($_POST))
{
.
.
.
.

Answer 1

I'm not familiar with the plugin you are using to handle the uploads, but if the form elements are hitting the PHP as they should, you simply can call
$fileId = $_POST['user_id'];
This will set a variable in your PHP Process equal to the hidden value. Make sure you include it within the ISSET conditional as not to cause any errors.

Answer 2

Just pass the information through the uploadURL:
input.upload(uploadURL + "?user_id=" + $("input[name=user_id]").val(), function(res) {});
Make sure the name of the hidden input holding the user id is 'user_id'.
Server side in PHP you can read the value of the variable with isset($_REQUEST['user_id']).