here the code,
<?php
$a = $_GET['Cors'];
$b = $_GET['sem'];
$c = $_GET['yrlvl'];
mysql_connect("localhost", "root", "") or die ('Error'.mysqlerror());
mysql_select_db("sched");
$query="INSERT INTO sked (crs,sm,yrlvl) values ('".$a."','".$b."','".$c."')";
mysql_query($query) or die ('Error Cannnot Insert Records!');
?>
<?php
the listbox is "sem", tnx