JavaScript Quiz

Here are some of the questions that I found in a book titled "Object-Oriented JavaScript" by Stoyan Stefanov.

    var a; typeof a;

    var s = 'ls'; s++;

    !!false;

    !!undefined;

    typeof -Infinity;

    10 % "0";

    undefined == null;

    false  === "";

    typeof "2E+2";

    a = 3e+3; a++;

    var v = v || 10;

    typeof NaN;