# Factorial of a number using JavaScript

Given a positive integer n and the task is to find the factorial of that number with the help of javaScript.

Examples:

```Input : 4
Output : 24

Input : 5
Output : 120
```

Approach 1: Iterative Method In this approach, we are using a for loop to iterate over the sequence of numbers and get the factorial.

Example:

 `  ` `<``html``>  ` ` `  `<``head``>  ` `    ``<``title``>  ` `        ``Factorial of a number using JavaScript ` `    `` ` `  ` ` `  `<``body` `style` `= ``"text-align:center;"``>  ` `     `  `    ``<``h1` `style` `= ``"color:green;"` `>  ` `        ``GeeksForGeeks  ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_UP"` `style` `= ` `        ``"font-size: 15px; font-weight: bold;"``> ` `    `` ` `         `  `    ``<``button` `onclick` `= ``"GFG_Fun()"``> ` `        ``Click Here ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_DOWN"` `style` `= ` `        ``"color:green; font-size: 20px; font-weight: bold;"``> ` `    `` ` `         `  `    ``<``script``> ` `        ``var up = document.getElementById('GFG_UP');  ` `        ``var down = document.getElementById('GFG_DOWN');  ` `        ``var n = 5; ` `         `  `        ``up.innerHTML = "Click on the button to calculate" ` `                ``+ " the factorial of n.<``br``>n = " + n; ` `         `  `        ``function Factorial(n) { ` `            ``var ans=1; ` `             `  `            ``for (var i = 2; i <= n; i++) ` `                ``ans = ans * i; ` `            ``return ans; ` `        ``} ` `         `  `        ``function GFG_Fun() {  ` `            ``down.innerHTML = Factorial(n); ` `        ``}  ` `    ``  ` `  ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

Approach 2: Recursive Method: In this approach, we are calling the same function again and again to get the factorial of a number.

Example:

 `  ` `<``html``>  ` ` `  `<``head``>  ` `    ``<``title``>  ` `        ``Factorial of a number ` `        ``using JavaScript ` `    `` ` `  ` ` `  `<``body` `style` `= ``"text-align:center;"``>  ` `     `  `    ``<``h1` `style` `= ``"color:green;"` `>  ` `        ``GeeksForGeeks  ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_UP"` `style` `=  ` `        ``"font-size: 15px; font-weight: bold;"``> ` `    `` ` `     `  `    ``<``button` `onclick` `= ``"GFG_Fun()"``> ` `        ``Click Here ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_DOWN"` `style` `=  ` `        ``"color:green; font-size: 20px; font-weight: bold;"``> ` `    `` ` `     `  `    ``<``script``> ` `        ``var up = document.getElementById('GFG_UP');  ` `        ``var down = document.getElementById('GFG_DOWN');  ` `        ``var n = 10; ` `         `  `        ``up.innerHTML = "Click on the button to calculate" ` `                ``+ " the factorial of n.<``br``>n = " + n; ` `         `  `        ``function Factorial(n) { ` `            ``if (n === 0) {  ` `                ``return 1;  ` `            ``} ` `            ``else {  ` `                ``return n * Factorial( n - 1 );  ` `            ``} ` `        ``} ` `         `  `        ``function GFG_Fun() {  ` `            ``down.innerHTML = Factorial(n); ` `        ``}  ` `    ``  ` `  ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

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