How to uncheck a group of checkbox in JQuery/JavaScript

I'm trying to keep either "All" and a group of checkboxes (1,2,3) is unchecked. For example, when "All" and "1" are checked, if I click "All", "1" should be unchecked, and vice versa.

<input type="checkbox" name="checkAll" class="selectAll" />  All  <br/>
<input type="checkbox" name="checkuser" class="cb_box "  />  1
<input type="checkbox" name="checkuser" class="cb_box "  />  2
<input type="checkbox" name="checkuser" class="cb_box "  />  3

I tried in this way but it doesn't work. Any suggestion?

$(function(){ $('.selectAll').click(function(){ $('input[name=checkuser]').attr('unchecked', $(this).attr('checked')); });