Modal dialogs should capture focus and retain it until closed. This requires:
Any input device should be able to close the dialog. This example uses focusable (tabbable) buttons as well as the ESC key. Focus should then return to the previously active element.
Accordingly these dialogs should work well with pointer devices (mouse, touch screen, etc.) or keyboard tabbing.
This demo uses CSS 3 and ECMA Script features which are not backwards compatible with Internet Explorer.
Internet Explorer 11 continues to receive security updates but it does not receive modern feature updates. Consequently sites which must support Internet Explorer cannot advance.
Microsoft is encouraging Windows users to switch to Edge as their default web browser.
You won't regret it.