use fontawesome in css code example

Example 1: link to font awesome

<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">

Example 2: how to use this in js

// In web browsers, the window object is also the global object:
console.log(this === window); // true

a = 37;
console.log(window.a); // 37

this.b = "MDN";
console.log(window.b)  // "MDN"
console.log(b)         // "MDN"