LockerService relies on some JavaScript features in the browser: support for strict
mode, the Map object, and the Proxy object. If a browser doesn’t meet the requirements,
LockerService can’t enforce all its security features and is disabled.
LockerService is disabled for unsupported browsers. If you use an unsupported browser, you’re
likely to encounter issues that won’t be fixed. Make your life easier and your browsing
experience more secure by using a supported browser.