title: removeClass() if it exists
body: <p>This function adds a <code>rotated</code> class to my button when I click it. The button has an arrow on it which points in the direction the panel has slid. </p>
  
  <p>How could I remove the rotated class when I click the button again?</p>
  
  <pre><code>$("#btnDiv").click(function (){
       $('#slidePanel').toggle( "slide",{direction: 'right'});
       $('#btnDiv').addClass('rotated');
  });
  </code></pre>
  
  <p>Something like this maybe?</p>
  
  <pre><code>if('rotated'){
      removeClass('rotated')
  }else{
      addClass('rotated')
  }
  </code></pre>