Dynamic count of checkboxes in a table

I have a table that display a jquery checkbox at the end of every row.  I would like to display the total number of checkboxes that are checked in the last row of the table.  Here is the table:

<table border="1">
                <tr>
	                <th></th>
                    <th style="vertical-align:middle;">Number</th>
                    <th style="text-align:left; vertical-align:middle;">Owner</th>
                    <th style="text-align:left; vertical-align:middle;">Address</th>
                    <th style="vertical-align:middle;">Code</th>
                    <th style="vertical-align:middle;">Class</th>
                    <th style="vertical-align:middle;">Filing Fee</th>
                    <th style="text-align:center; width:70px;">Review ?<br /><span style="text-decoration:underline; cursor:pointer;" onclick="select_all_com()">All</span> &nbsp;&nbsp;&nbsp;
					<span style="text-decoration:underline; cursor:pointer;" onclick="select_none_com()">None</span></th>
                </tr>

                <?php foreach ($property['commercial'] as $key => $value): ?>
                    <tr>
                    	<th><?php echo str_pad($row++, 2, '0', STR_PAD_LEFT); ?></th>
                        <td><a href= "<?php echo site_url() . "propertydetail/viewpropertydetail/" . $value['property#']; ?>"><?php echo Roll($value['property#']); ?></a></td>
                        <td style="text-align:left"><?php echo $value['Property Owner']; ?> </td>
                        <td style="text-align:left"><?php echo $value['Property Address']; ?></td>
                        <td style="text-align:middle" ><?php echo number_format($value['PC'],0); ?></td>
						<td><?php echo $value['Class']; ?></td>
                        <td><?php echo money_format('$%.0i', 140); ?></td>
                        <td id="com" style="padding-left:23px;">
                        	<input type="checkbox" name="file_com_appeal" class="com-checkbox" value="<?php echo $value['property#'] ?>">                            
                        </td>                                            
                    </tr>
                <?php endforeach; ?>
                    <th colspan="6" style="text-align:right; padding:1% 3% 1% 0%;"><h4>Total</h4></th>
                    <th><?php echo "NEED COUNT OF THE CHECKED CHECKBOXES HERE"; ?></th>
                    <th></th>
            </table>

Could someone please help me to understand how to keep track of the number of checkboxes that are checked?  By the way, this needs to update itself with each checkbox that is changed.

Thank you.