Script not responding errors (not here)

[Oniya]

Every so often, when I'm visiting certain sites, my computer will hang for a bit and then I'll get an error saying 'A script on this page has stopped responding' with options to 'Continue' (hangs for a little longer and then pops up the message again), 'Debug script' (gives me a lot of code that I don't understand and don't have access to modify anyways) or 'Stop script' (usually clears the problem, but may crash apps on other pages.)  The error popup is accompanied by my browser switching to a specific tab or window, which I assume is the location of the problem script.

It recently started happening on a puzzle site that I'm on, and I posted to their tech support, who - without asking me anything about my setup - said that the problem was related to my browser:

the [puzzle] solver is written in Javascript and uses SVG for renderig. For some browsers the SVG support is not very good. You know, there are thousands triangles especailly for large [puzzles]. Please try another browser, maybe it will be better.
Rasto

I responded with:
Which browsers, in your estimation, have the best SVG support?
   
(Meanwhile, I did some research and found that the major difference between the 'big name' browsers and SVG support has to do with stacking of filter primitives.  The symptom of issues related to that isn't 'script errors', but actual faults in the image display, like rendering Gaussian blur or text around a path.  Also, the article that I found referencing that dates back to Firefox 38.0.5, and I'm using 50.1.0, so I imagine that improvements to this have been made.)
   
They've now given me the response of:

I have pretty fast coputer with MacOS and I can see that Firefox is much faster than Chrome on large [puzzles]. On Windows it may be different.

Other than the Mac aspect, this guy is using the same setup I am.   ::)