This doesn't make sense here (as exceptions are thrown by the method and not "raised" at objects - see http://dev.w3.org/2006/webapi/WebIDL/#dfn-throw):

> <code>NotSupportedError</code> MUST be raised on the <a><code>TelephonyManager</code></a> object. 

It should just say:

> `<a href="http://dev.w3.org/2006/webapi/WebIDL/#dfn-throw">` throws`</a>` a  `<code>NotSupportedError</code>` exception.