Ajax to check file size and type before uploading

Hi, I am trying to write a script that checks the size and type of a file as it is selected, without submitting the form:

<input name=”uploadedfile” type=”file” onchange=”ajax_check_image()”/>

The Ajax function basically looks like this:

//Opens and sends the ajax request
ajax_request.open(“GET”,”functions/check_image_file.php”,true);
ajax_request.send(null);

And then the script it calls looks like this:

<?php

//Checks if the image is the right file type and less than 100k.
if ((($_FILES[“uploadedfile”][“type”] == “image/gif”)
|| ($_FILES[“uploadedfile”][“type”] == “image/jpeg”)
|| ($_FILES[“uploadedfile”][“type”] == “image/pjpeg”))
&& ($_FILES[“uploadedfile”][“size”] < 100001))
{
//If
if ($_FILES[“uploadedfile”][“error”] > 0)
{
echo ($_FILES[“uploadedfile”][“error”] . ” is an invalid image file”);
}
else
{
echo ($_FILES[“uploadedfile”][“name”] . ” is an valid image file”);
}
}
else
{
echo “Invalid file”;
}
?>

The problem is that the PHP $FILES[][] only picks up the files if it has been submitted from a form.

Is there anyway to check the file without submitting the form?

Thanks in advance.

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