title: jQuery function source code
body: <p>jQuery 1.4.2 in IE 8  </p>
  
  <p>When I call <code>$.isFunction(function() {})</code> it returns <code>true</code>.<br>
  Source code <code>isFunction</code> function:</p>
  
  <pre><code>    isFunction: function (obj) {
          return toString.call(obj) === "[object Function]";
      },
  </code></pre>
  
  <p>When I write in console <code>toString.call(function() {}) === "[object Function]"</code> it throws <code>"Object doesn't support this property or method"</code>.</p>
  
  <p>Source code of minified version:</p>
  
  <pre><code>isFunction:function(a){return $.call(a)==="[object Function]"}
  </code></pre>
  
  <p>When I write in console <code>$.call(function() {})==="[object Function]"</code> it returns <code>false</code>.<br>
  Why code works in different ways?</p>