Checks If Browser Tab & Browser Window Gain Or Lose Focus Using The HTML5 Visibility API
TAB FOCUS
TAB BLUR
WINDOW FOCUS
WINDOW BLUR
To Test
:
-
First click inside the Preview panel so the page gains focus (
very important
)
-
Switch between tabs
-
Give another program (or one of the CodePen editor panels) focus and come back to the browser
-
Look at the above state changes.