title: dynamic check/uncheck of checkboxes
body: <p>There are plenty posts about checking/unchecking checkboxes dynamically but I suppose my is a little bit diferent.
  My checkbox is mulitple values checkbox (I use it to parametrize graph) where data comes from query somthing like:</p>
  
  <p><i></p>
  
  <pre><code>select 'all' as val from dual
  union
  select name_of_month as val from months
  </code></pre>
  
  <p></i></p>
  
  <p>So the result is 13 checkboxes : [0] (all)  [1]-[12] (jan feb mar etc.) </p>
  
  <p>What I would like to get is below behaviours</p>
  
  <ul>
  <li>when I check (all)  all 13 checkboxes will check</li>
  <li>when I uncheck (all)  all 13 checkboxes will uncheck</li>
  <li>when I uncheck one of 1-12 checkboxes and (all) is checked  will uncheck </li>
  <li>when all 12 checkboxes are checked one by one checkbox will also be checked</li>
  </ul>
  
  <p>I am not sure if description above is clear enough but I believe You feel how this checkbox should work</p>
  
  <p>UPDATE:
  I am Oracle DBA (with basic knowledge of JavaScript) who try to create something in APEX. Until I use wizzards and mouse to draw objects it is easy.  Right now I see I have to type a few lines of code so please give me at least some explanation where to type it and how to run it to let it work. </p>