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How to generate random number in given range using JavaScript ?

• Difficulty Level : Medium
• Last Updated : 12 Jan, 2023

A number generated by a process, whose outcome is unpredictable is called Random Number. In JavaScript, this can be achieved by using Math.random() function. This article describes how to generate a random number using JavaScript.

Method 1: Using Math.random() function.

The Math.random() function is used to return a floating-point pseudo-random number between range [0,1), 0 (inclusive), and 1 (exclusive). This random number can then be scaled according to the desired range.

Syntax:

`Math.random();`

Example 1: This example generates an integer random number between 1(min) and 5(max).

JavaScript

 `// Function to generate random number ` `function` `randomNumber(min, max) { ` `    ``return` `Math.random() * (max - min) + min; ` `} ` ` `  `console.log(``"Random Number between 1 and 5: "``) ` ` `  `// Function call ` `console.log( randomNumber(1, 5) );`

Output:

`Random Number between 1 and 5: 1.0573617826058959`

Method 2: Using Math.floor() function.

The Math.floor() function in JavaScript is used to round off the number passed as a parameter to its nearest integer in the Downward direction of rounding i.e towards the lesser value.

Syntax:

`Math.floor(value)`

Example 1: This example generates a random integer number between 1(min) and 100(max).

JavaScript

 `// Function to generate random number ` `function` `randomNumber(min, max) { ` `    ``return` `Math.floor(Math.random() * (max - min) + min); ` `} ` ` `  `console.log(``"Random Number between 1 and 100: "``) ` ` `  `// Function call ` `console.log( randomNumber(1, 100) );`

Output:

`Random Number between 1 and 100: 87`

Example 2: This example generate random whole number between 1(min) and 10(max) both inclusive.

JavaScript

 `// Function to generate random number ` `function` `randomNumber(min, max) { ` `    ``min = Math.ceil(min); ` `    ``max = Math.floor(max); ` `    ``return` `Math.floor(Math.random() * (max - min + 1)) + min; ` `} ` ` `  `console.log(``"Random Number between 1 and 10: "``) ` ` `  `// Function call ` `console.log( randomNumber(1, 10) );`

Output:

`Random Number between 1 and 10: 3`

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