Using the CSGO Marketplace API to fetch data via JSONP request fails for me

[Gambelix]

I'm trying to fetch data from the backpack.tf Market API so I wrote this code (in Javascript (JQuery preloaded), executed through a Chrome extension):

$.ajax({

url: "https://backpack.tf/api/IGetMarketPrices/v1",

   dataType: "jsonp",

   type: "GET",

   data: {

      format: 'jsonp',

      key: 'XXX',

      appid: 730,

      callback: "?"

   },

   success: function( response ) {

      console.log( response );

   }

});

However Chrome throws an error: "Uncaught ReferenceError: jQuery31102767713451557141_1486009880600 is not defined". For me, that seems like JSONP is not supported, but from the documentation, it should be. I really hope this is just me doing a stupid mistake, so it would be nice if someone could tell me which. 

[Erik]

/summon cares

/summon Fiskie

 

Good luck though