Firefox Javascript Error

[batyuvitez]

I am using your awesome script.
Works perfectly with all browsers except Firefox. . I am using version 55.03

Error are different. Most common that Firefox ends the execution of script in line #58: "for (y = j = 0, ref1 = canvas.height; 0 <= ref1 ? j <= ref1 : j >= ref1; y = 0 <= ref1 ? ++j : --j) {"

Example: https://www.kezikonyvunk.hu