Code:
var diggurl = 'http://services.digg.com/topics?appkey=http%3A%2F%2Fwww.myappkey.com%2Fmyapp';
       var req =  new Ajax.Request(diggurl,{
         method: 'get',
         evalJSON: 'force',
         contentType: 'application/json',
         onSuccess: function(r){
            Mojo.Log.info("IT WORKED!");
            Mojo.Log.info(r.responseJSON);
         }.bind(this),
         onFailure: function(r){
            Mojo.Log.info("IT FAILED!")
         }.bind(this)
       });
Pretty simple code, this URL works in the browser but here it fails. I think I'm probably making an obvious mistake, but for the life of me I can't figure out what it.

I run this and every time I get the IT FAILED message. I have tried escaping my forward slashes, even replacing them with %2F and it doesn't matter. Obviously my problem is elsewhere. Any ideas?