<script type="text/javascript" src="//code.jquery.com/jquery-1.8.0.min.js"></script>
<input type="button" class="check" value="check all" />
</br>
<input type="checkbox" class="cb-element" /> Checkbox 1</br>
<input type="checkbox" class="cb-element" /> Checkbox 2</br>
<input type="checkbox" class="cb-element" /> Checkbox 3</br>
<script>
$(document).ready(function(){
$('.check:button').toggle(function(){
$('input:checkbox').attr('checked','checked');
$(this).val('uncheck all')
},function(){
$('input:checkbox').removeAttr('checked');
$(this).val('check all');
})
})
</script>