Hi, I have some questions/remarks about your code:
1) Is there a particular reason you're creating a script element and not something else?
2) Is there a particular reason you're appending to documentElement and not to body?
3) I think setting it to none and checking for that would be better, in the hypothetical case a browser has it present but read-only. auto is the default value.
4) Why getPropertyValue('pointer-events') instead of just .pointerEvents? Are there any browser support issues of the latter?
5) If getComputedStyle isn't present, undefined will be returned instead of false.
fixed Issue #1