I am DIV One. On focus my text will change to tell you I have focus. On loss of focus my text will change to tell you that I have lost focus. But you will never see this text again.

I am DIV Two. I do nothing on focus.

I am DIV Three. On focus, I will display a "Hello World" alert. On loss of focus , I will display a "Goodbye World" alert. My text will remain unchanged.