<script>
    $(document).ready(function(){
        $(".uni_type").click(function(){
            uni_type = this.id;
            location.href = "filter-colleges.php?uni_type="+uni_type;
        });
    });
</script>

<ul>
   <li class="uni_type" id="central university">Central University</li>
   <li class="uni_type" id="state university">State University</li>
   <li class="uni_type" id="private university">Private University</li>
   <li class="uni_type" id="deemed university">Deemed University</li>
   <li class="uni_type" id="open university">Open University</li>
   <li class="uni_type" id="autonomus">Autonomus Institute</li>
</ul>

<?php
   include('conn.php');
   $uni_type = $_GET['id'];
   echo '<script>alert('.$uni_type.')</script>';