title: delete cookie with specific name
body: <p>I wold like to use javascript to delete a cookie , the cookie name is "orinet" , I find the link
  <a href="https://stackoverflow.com/questions/10593013/delete-cookie-by-name">Delete cookie by name?</a> and change it to as below , but do not work , after run it , the cookie is still exist .
  What I would like to do is just remove the specific cookie ( or rename it , something like that ) , could advise what is wrong ? or could advise work around method to do it ? thanks </p>
  
  <pre><code>&lt;script&gt;
  function del_cookie(name) {
      document.cookie = 'roundcube_sessauth' + 
       '=; expires=Thu, 01-Jan-70 00:00:01 GMT;';
       } 
       &lt;/script&gt;
  
     &lt;a href="javascript:del_cookie(orinet);"&gt;KILL&lt;/a&gt;
  </code></pre>