<?php
$edit_data      = $this->db->get_where('prescription', array('prescription_id' => $param2))->result_array();
foreach ($edit_data as $row):
$patient_info   = $this->db->get_where('patient' , array('patient_id' => $row['patient_id'] ))->result_array();
?>
    <div id="prescription_print">
        <table width="100%" border="0">
            <tr>
                <td align="left" valign="top">
                    <?php foreach ($patient_info as $row2){ ?>
                        <?php echo 'Patient Name: '.$row2['name']; ?><br>
                        <?php echo 'Age: '.$row2['age']; ?><br>
                        <?php echo 'Sex: '.$row2['sex']; ?><br>
                    <?php } ?>
                </td>
                <td align="right" valign="top">
                    <?php $name = $this->db->get_where('doctor' , array('doctor_id' => $row['doctor_id'] ))->row()->name;
                          echo 'Doctor Name: '.$name;?><br>
                    <?php echo 'Date: '.date("d M, Y", $row['timestamp']); ?><br>
                    <?php echo 'Time: '.date("H:i", $row['timestamp']); ?><br>
                </td>
            </tr>
        </table>
        <hr>
        <div class="row">
            <div class="col-md-12">

                <div class="panel panel-primary" data-collapsed="0">

                    <div class="panel-body">

                        <b><?php echo get_phrase('case_history'); ?> :</b>

                        <p><?php echo $row['case_history']; ?></p>

                        <hr>

                        <b><?php echo get_phrase('medication'); ?> :</b>

                        <p><?php echo $row['medication']; ?></p>

                        <hr>

                        <b><?php echo get_phrase('note'); ?> :</b>

                        <p><?php echo $row['note']; ?></p>

                    </div>

                </div>

            </div>
        </div>
    </div>
    <br>

    <a onClick="PrintElem('#prescription_print')" class="btn btn-primary btn-icon icon-left hidden-print">
        Print Prescription
        <i class="entypo-doc-text"></i>
    </a>
<?php endforeach; ?>



<script type="text/javascript">

    function PrintElem(elem)
    {
        Popup($(elem).html());
    }

    function Popup(data)
    {
        var mywindow = window.open('', 'prescription', 'height=400,width=600');
        mywindow.document.write('<html><head><title>Prescription</title>');
        mywindow.document.write('<link rel="stylesheet" href="assets/css/neon-theme.css" type="text/css" />');
        mywindow.document.write('<link rel="stylesheet" href="assets/js/datatables/responsive/css/datatables.responsive.css" type="text/css" />');
        mywindow.document.write('</head><body >');
        mywindow.document.write(data);
        mywindow.document.write('</body></html>');

        mywindow.print();
        mywindow.close();

        return true;
    }

</script>

maybe if you tell what isn't working

pzuurveen javascript functions are not working

functions are not working

It would be more helpful if you stated what is supposed to happen, and what doesn't happen. "It's not working" is too vague for any question.