var - variables in JavaScript

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examples/js/var.js

"use strict";

var user_name = 'Foo';
console.log(user_name); // "Foo"

var age = 42;
console.log(age);  // 42

age = 23;
console.log(age);  // 23

user_name = 1;
console.log(user_name); // 1

var email;
console.log(email); // undefined

email = 'foo@bar.com';
console.log(email);  // foo@bar.com

• "use strict"; (later explained)
• Declare variables using 'var'
• Variable names start with letters, underscore (_), or the dollar sign.
• Variable names can contain letters, underscore (_), the dollar sign, and digits.
• camelCase is the recommended style in JavaScript, though I think long_names separated with underscores are nicer.