JavaScript Spiral / jsfiddle vs verbatim HTML file

Question

Originally I thought making a spiral with JS would be a good learning project. I'm not great with math so it would take me a looong time to figure out the equations myself so I just retyped a jsfiddle verbatim to see some code and get it in muscle memory. After I finished though, it won't work for me client side. I'm getting this error from Chrome:

spiral.js:2 Uncaught TypeError: Cannot read property 'getContext' of null
at spiral.js:2

From this code line:

var context = c.getContext("2d");

the jsfiddle:

http://jsfiddle.net/jingshaochen/xJc7M/

But this js fiddle is the exact same and it generates a spiral and works. Is this something to do with a frame work around it?? I would appreciate any input greatly.

Answer 1

JSFiddle adds JS after the elements are loaded, so maybe some of the recommendations in this post can help you:

https://www.sololearn.com/post/7444/?ref=app