Examples in Action: Using "this" with Functions

Example: A function invoked using Function.call

var myObject = {
sayHello : function() {
console.log('Hi! My name is ' + this.myName);
},
myName : 'Rebecca'
};
var secondObject = {
myName : 'Colin'
};
myObject.sayHello();                  // logs 'Hi! My name is Rebecca'
myObject.sayHello.call(secondObject); // logs 'Hi! My name is Colin'

Example A function created using Function.bind

var myName = 'the global object',
sayHello = function () {
console.log('Hi! My name is ' + this.myName);
},
myObject = {
myName : 'Rebecca'
};
var myObjectHello = sayHello.bind(myObject);
sayHello();       // logs 'Hi! My name is the global object'
myObjectHello();  // logs 'Hi! My name is Rebecca'

Example: A function being attached to an object at runtime

var myName = 'the global object',
sayHello = function() {
console.log('Hi! My name is ' + this.myName);
},
myObject = {
myName : 'Rebecca'
},
secondObject = {
myName : 'Colin'
};
myObject.sayHello = sayHello;
secondObject.sayHello = sayHello;
sayHello();               // logs 'Hi! My name is the global object'
myObject.sayHello();      // logs 'Hi! My name is Rebecca'
secondObject.sayHello();  // logs 'Hi! My name is Colin'

Source: Rebecca Murphey, https://autotelicum.github.io/Smooth-CoffeeScript/literate/js-intro.html#the-this-keyword
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.