I am new to PHP.
When someone uploads a file size too big, I want to show them a warning popup and redirect them to a previous page (or vice versa).
if(file size is too big){
ob_start();
header("location:index.php");
echo "<script type='text/javascript'>alert('Your File Size is too big!');</script>";
ob_end_flush();
exit;
}
This code above will just redirect me to index.php and doesn't show any warning popup.