I don't know if it's your fault, firefox's fault or greasemonkey's fault, but it's crashing at line 1437 o.observe(document.head Because at this stage document.head is null. Thus it can be fixed by encapsulating the function in setTimeout with delay = 0. ¯\_(ツ)_/¯
Your script is broken on firefox nightly
I don't know if it's your fault, firefox's fault or greasemonkey's fault,
but it's crashing at line 1437 o.observe(document.head
Because at this stage document.head is null.
Thus it can be fixed by encapsulating the function in setTimeout with delay = 0. ¯\_(ツ)_/¯