The Problem:
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'http://internet.derp' is therefore not allowed access.

The Solution:
A CORS proxy!

$.getJSON('https://blockchain.info/stats?format=json',function(){})

becomes ..

$.getJSON('http://cors.io/?u=https://blockchain.info/stats?format=json',function(){})