title: Javascript add month to variable
body: <p>I've a variable in Javascript such as:  </p>
  
  <pre><code>var a = "2015/05/04";
  </code></pre>
  
  <p>How do I add/subtract months to the variable such as:   </p>
  
  <pre><code>a.getMonths() + 1;    
  </code></pre>
  
  <p>that will result in "2015/06/04"</p>
  
  <p>I tried to do the getMonths() and the alert is not displaying the result.</p>