• Hoisting
  • Declarations are Hoisted
  • Const and Let

Hoisting VS. Declaration

Hoisting

• Hoisting is JavaScript’s default behavior of moving all declarations to the top of the current scope (to the top of the current script or the current function)

  Declarations are Hoisted

• a variable can be used before it has been declared ```js x = 5; 

elem = document.getElementById(“demo”);
elem.innerHTML = x;   

var x; 

## Initializations are Not Hoisted
```js
var x = 5; 
  
elem = document.getElementById("demo");   
elem.innerHTML = x + " " + y; //y is undifinded          
  
var y = 7;

Const and Let

• Variables defined with let and const are hoisted to the top of the block, but not initialized

  name = "Jane";  
  let name;   //referenceError