check / uncheck box

[iseriouslyneedhelp]

I can't figure out why this doesn't work, it checks but doesn't uncheck:

 

Javascript:

$( function() {         
$( '.checkAll' ).live( 'change', function() {             
$( '.checkall' ).attr( 'checked', $( this ).is( ':checked' ) 
? 'checked' : '' );             
$( this ).next().text( $( this ).is( ':checked' ) ? 'Uncheck All' : 'Check All' );         
});         
$( '.checkall' ).live( 'change', function() {             
$( '.checkall' ).length == $( '.checkall:checked' ).length ? $( '.checkAll' ).attr( 'checked', 'checked' ).next().text( 'Uncheck All' ) : $( '.checkAll' ).attr( 'checked', '' ).next().text( 'Check All' );          
});     
});

 

HTML:

   <tbody>
    <tr> 
    <td width=""><input type="checkbox" name="checkall" class="checkall" value="<?php echo $row['ID']; ?>"></td>
    <td width=""><a href="/backend/contacts/editcontact.php?ID=<?php echo $row['ID']; ?>"><strong><?php echo $row['firstname']; ?> <?php echo $row['lastname']; ?></strong></a></td>
    <td width=""><?php echo $row['phonecell']; ?> </td>
    <td width=""><a href="<?php echo $row['email']; ?>"><?php echo $row['email']; ?></a> </td>
<td width=""><?php echo $row['contactstatus']; ?> </td>
    <td width=""><?php echo $row['contacttype']; ?> </td>
<td width=""><?php echo $row['type']; ?> </td>
    <td><? echo date("F d, Y", strtotime($row['reminder'])); ?></td>
    <td><a href="/backend/contact/notes.php?ID=<?php echo $row['tasknotes']; ?>">Notes</a></td>
    <td><a href="/backend/call-center/callcenter.php?ID=<?php echo $row['ID']; ?>">Call</a></td>
    <td><a href="mailto:<?php echo $row['email']; ?>">Email</a></td>
    <td><a href="/backend/contacts/deletesuccess.php?ID=<?php echo $row['ID']; ?>">Delete</a></td>
   </tr>
   </tbody>