title: jquery .off doesn't seem to work
body: <p>so I'll be short: jquery <code>.off()</code> doesn't disable a listen I've set with <code>.on</code>.</p>
  
  <p>html:</p>
  
  <pre><code>&lt;span id="myspan"&gt;lol&lt;/span&gt;
  &lt;button id="b1"&gt;jquery On&lt;/button&gt;
  &lt;button id="b2"&gt;jquery Off&lt;/button&gt;
  </code></pre>
  
  <p>js:</p>
  
  <pre><code>$("#b1").on("click", add);
  $("#b2").on("click", del);
  
  function add() {
      $("#myspan").on("click", function(e) {
          var a = 1;
          testfunc(a, e);
      });
  }
  
  function del() {
      $("#myspan").off("click", testfunc);
  }
  
  function testfunc(num, event) {
     alert(num);
  }
  </code></pre>
  
  <p>So first we add to <strong>myspan</strong> the <code>testfunc()</code> by clicking the <em>jquery On</em> button. After we do that, if we click on the span, we get an alert. Next, we click the <em>jquery off</em> button. That is supposed to remove the listener but it doesn't. Even after that, when we click on <strong>myspan</strong> <code>testfunc</code> is still attached.</p>
  
  <p>Why? And how can I remove it ?</p>