iOS 10 Safari JavaScript setting disabled

Solution 1:

I've discovered mine had this issue due to my corporate email app restricting JavaScript on safari, post update

Solution 2:

The following is based on my observation.

By default the Safari JavaScript is enabled, because most of the website that I visited that extensively using JavaScript are working in Safari. The problem starts only when I Clear History and Website Data and go to Settings > Safari > Advanced.

I think as soon as you hit Advanced "for the first time" the program just has an issue as no previous settings are set, thus setting itself to Disable.

I exited from settings and visit the previous website that are using JavaScript, obviously all of them either don't show up or become a Dumb website except you click a link that uses anchor.

Solution: Just go to Advanced again and set Enable the JavaScript setting. Next time you visit this remain enabled.