2th of 19 Questions.
What is the default binding of this? How does strict mode change it?
Default binding in non-strict mode sets this to the global object (window in browsers, global in Node.js). In strict mode, this defaults to undefined.
Default binding occurs when a function is called standalone, not as a method, not using new, and not using explicit binding. In non-strict mode, this defaults to the global object (window in browsers, global in Node.js). In strict mode ('use strict'), this defaults to undefined to prevent accidental global pollution. Example: function show() { console.log(this); } show(); // In non-strict: global object; in strict: undefined.