Visualize.js: Cannot read property '2' of null

Issue description

A script which uses Visualize.js API fails to run and produced the following error in browser log:

Cannot read property '2' of null

Cause and solution

This error is thrown when trying to run a script from a local file. For example, when your browser path looks something like file:///C:/Users/Desktop/index.html

The URL in such case starts will file://* which is not supported by Visualize.js. The URL has to start from http(s)://*. This limitation is imposed for security reasons.