<https://w3schools.invisionzone.com/topic/53171-problem-with-blur/#comment-293024>
<http://schema.org/text>
"Blur and focus methods aren't as reliable as they used to be. Once browsers started using tabs then those methods became less useful. Some browsers may still have those methods work like they used to, others might not. Try your code in different browsers to see how each of them work. "
<https://w3schools.invisionzone.com/topic/53171-problem-with-blur/?tab=comments#comment-293006>