on iOS 10, executing codes that try reading or accessing localStorage via javascript will return DOM Security 18: the operation is insecure. error.
I noticed this bug on iOS 10 b1 and it still happens on iOS 10 b2.
It runs A-OK on iOS 9.
I wonder if there's any API changed on iOS 10 or it's just another bug. I filed a bug on bugreporter but hope to hear if this happens to others.
* note: the html/js files are locally loaded.