title: returnTrue and returnFalse functions in jQuery source
body: <p>I can't help but notice there are two seemingly useless functions in the source code of jQuery (For v1.9.1, it's line 2702 and line 2706):</p>
  
  <pre><code>function returnTrue() {
      return true;
  }
  
  function returnFalse() {
      return false;
  }
  </code></pre>
  
  <p>Which both are called quite often within jQuery. Is there a reason why they don't simply substitute the function call with a boolean <code>true</code> or <code>false</code>?</p>