Hi Saludos
I must admit that I've made OPTICS just for Firefox, so the class might not work in every browser like Chrome. There is a bug in the Chrome-Browser that constrains that a webworker (main_worker) can contain sub-webworker. This should not happened but may be there are no developers with google that want to fix the bug :). The bug is 2 or 3 years old approximately.
I've done little investigation in terms of the "Uncaught Error: SecurityError: DOM Exception 18"-Error, Stackoverflow is always worth to have a look at. Have you run the optics_cluster_with_webworker.html-example without a server, if so then this is may the reason:
stackoverflow.com/questions/2704929
...
The optics_cluster_with_webworker.html-Example was made for a scientific work, the OPTICS-algo itself actually does not need webworker in order to work. The example was made for running OPTICS with a lot of different epsilon and minPTs-values simultaneously.
I hope this helps you and answered your question as well.
ˇHa sido un placer!
Josef