# what is hosting

## **What is Hoisting?**

**Hoisting** is JavaScript's default behavior of **moving declarations (not initializations) to the top of their scope** (global or function) during the **memory creation phase**.

In reality, nothing is physically moved.  
It’s just that **variable and function declarations are stored in memory before code execution starts**.

---

## **How Hoisting Works**

JavaScript executes code in two phases for each execution context (Global or Function):

1. **Creation Phase (Memory Allocation)**
    
    * Variables (`var`) are hoisted with value `undefined`.
        
    * Functions (function declarations) are hoisted with their **full definition**.
        
2. **Execution Phase**
    
    * Code runs line by line.
        
    * Variable assignments happen here.
        

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## **Examples**

### **1\. Hoisting with** `var`

```javascript
console.log(x); // undefined
var x = 5;
console.log(x); // 5
```

Why `undefined`?

* During creation phase: `x = undefined`.
    
* During execution: `x = 5`.
    

---

### **2\. Hoisting with Functions**

```javascript
greet(); // Hello!

function greet() {
    console.log("Hello!");
}
```

Works fine because the entire function is hoisted.

---

### **3\. Function Expression (Not Hoisted Like Declarations)**

```javascript
greet(); // TypeError: greet is not a function

var greet = function() {
    console.log("Hello!");
};
```

Here, only the **variable name** `greet` is hoisted as `undefined`, not the function body.