<input name="msgId" value=msgId type="checkbox">
<a href="#" onclick="checkAll(document.viewForm.msgId); return false;">all</a>
<a href="#" onclick="uncheckAll(document.viewForm.msgId); return false;">none</a>
<a href="#" onclick="checkAll(document.viewForm.msgId); return false;">all</a>
<a href="#" onclick="uncheckAll(document.viewForm.msgId); return false;">none</a>