Why is it undefined?

Question

What is proid used for? urldecode($_GET['proid']) reports error

$rs2=mysqli_query($link,"select * from lend where book_id='".$rows['id']."' and user_id=' ".$_SESSION['id']."'");

$_SESSION['id'] reports an error, how to correct it?

Solution

Answer 1

Print out the $_SESSION array, and is the session open?