global object in javascript

1//Access Global variable
2var foo = "foobar";
3foo === window.foo; // Returns: true
4
5
6//Accessing Global Functions
7function greeting() {
8   console.log("Hi!");
9}
10
11window.greeting(); 
12

1var x = {name: "John"};	// This is a global object
2for(let i=0; i<10; i++){
3  	// Variable x is alive here
4	// Variable i is alive here
5  	
6  	let a = 3;
7  	// Variable a is alive here
8  	
9  	var y = 0;
10  	// Variable y is alive here
11}
12// Variable i is dead here
13// Variable a is dead here
14// Variable x is alive here
15// Variable y is alive here
16console.log(x);	// {name: "John"}
17console.log(y); // 0