broken_scope.js

#! /usr/bin/env node

var foo = function() {
    console.log("foo's x: %s BEFORE IT ENTERS SCOPE", x);
    x = "xb";
    y = "ya";
    return 0
}

var main = function() {
    x = "xa";
    console.log("main's x1: %s", x);
    foo();
    console.log("main's x2: %s", x);
    console.log("main's y: %s, WHICH IT HAS NEVER SEEN BEFORE", y);
}

main()

@rehia @AeroNotix: Yep. See the gist about loops, which includes output of versions with and without "use strict": https://gist.github.com/xandkar/9a422ea5cf01408a9d67fa4800e53b25

:)