title: How do I add a new key:value pair in existing JavaScript object?
body: <p>I have a JavaScript object like:</p>
  
  <pre><code>appointerment= {ids: '15,16,17', appointments: {'15': '12.05.2010,14,05,2010'} }
  </code></pre>
  
  <p>now in appointments object I want to add something like <code>'16': '21.05.2010'</code></p>
  
  <p>what is the best possible way to do this?</p>