When is the second parameter of prompt useful in which cases can we use it?

Answer 1

Second parameter in prompt mostly comes up as a placeholder like in HTML input tag!

Answer 2

Yeah but placeholder remains in background while the text in this case stays and we have to erase it to write anything...

Answer 3

the second parament can be an empty string like this

ex.

prompt("how are you today?", " ");

because some browsers will put undefined if no second parameter is defined