'Need help on Checkbox onclick jquery

trying to learn jquery and made a simple checkbox with a function where you can make all the options read-only checking on "none of the above" button.

<html>
  <body>

    <form id="diagnosedForm">
      <div>
      <input type="checkbox" value="1"/>1
      <br/>
      <input type="checkbox" value="2"/>2
      <br/>
      <input type="checkbox" value="3"/>3
      <br/>
    </form><br/>
    <input type="checkbox" value="" onclick="enableDisableAll(this);"/>None of the above

    <script src="script.js">
    </script>

  </body>
</html>

 function enableDisableAll(e) {
   var own = e;
   var form = document.getElementById("diagnosedForm");
   var elements = form.elements;

 for (var i = 0 ; i < elements.length ; i++) {
   if(own !== elements[i] ){
     if(own.checked == true){
       elements[i].disabled = true;
       elements[i].checked = false;
     }else{ 
       elements[i].disabled = false;  
       }
     }
   }
 }

this will be the output