Check whether channel is online or not via js [SOLUTION FOUND]

API
6

Sorry, I just looked at your screenshot and now I see the issue. I thought you meant the CORS error that is displayed when querying the endpoint without jsonp.

You need to include a script reference to jQuery before making the request like so:

<script src="//code.jquery.com/jquery-1.11.2.min.js"></script>

(place it above your existing <script> tag )

The //logic here will execute when the request succeeds, it really should have an error function declared too like so:

$.ajax({ 
     url:'https://api.twitch.tv/kraken/streams/Jonathan_x64',
     dataType:'jsonp',
     success:function(channel) { 
          //request succeeded, check channel status here
     },
     error:function() {
          //request failed
     }
 });