# Random Number Generator Javascript

In this tutorial, we will learn how to generate random numbers in javascript and we use a special method in javascript i.e.The Math.random() static method returns a floating-point, pseudo-random number that’s greater than or equal to 0 and less than 1, with approximately uniform distribution over that range — which you can then scale to your desired range. The implementation selects the initial seed to the random number generation algorithm; it cannot be chosen or reset by the user.

## Math random() Syntax in JS

``Math.random();``

In Javascript random number simple syntax would be –

## Math.random() Example in JavaScript

### Example 1 :

``````const a = Math.random();

console.log(a);  // generating a random number``````

### Output :

``0.5856407221615856``

Here, we have declared a variable a and assigned it a random number greater than or equal to 0 and less than 1.

### Example 2 :

How to get a javascript Random Number between 1 and 10.

``````const a = Math.random() * (10-1) + 1
console.log(`Random value between 1 and 10 is \${a}`);  // generating a random number``````

### Output :

``A random value between 1 and 10 is 1.1488764328463117``

### Example 3 :

How to get a random value between the range of 1 to 10.

``````const a = Math.floor(Math.random() * (10 - 1)) + 1;
console.log(`Random value between 1 and 10 is \${a}`); // generating a random number``````

### Output :

``Random value between 1 and 10 is 5``

For JavaScript random number, we used the Math.random() function. This method returns the value between 0 (inclusive) and 1 (exclusive).

This will show integer output between 1 (inclusive) to 10 (exclusive), i.e. (1 to 9). Here, Math.floor() is used to convert decimal to integer value.

## Define a function to generate random numbers

From the above concept, we can create a function that takes two arguments, the highest and lowest to generate a random number between them and returns it.

Below is the code to define a function to return a random number from a given range :

``````function generateRandomNumber(lowest, highest) {
let randomNumber = Math.random() * (highest - lowest) + lowest;
randomNumber = Math.floor(randomNumber);
return randomNumber;
}``````

These functions can be called whenever there is a requirement of generating a random number, it is better to create a function instead of repeating the whole processor, again and again, to generate random numbers in different blocks.

Calling the above function :

``````const randomNumber = generateRandomNumber(1, 1000);
console.log(randomNumber);``````

### Output :

``345``

Similar to the Math.random() function, the Math.floor() function will generate a random number, but this function rounds down the number to the nearest whole number.

### Syntax :

``Math.floor(x);``

### Example :

``````function randomNumber(minimum, maximum) {
return Math.floor(Math.random() * (maximum - minimum) + minimum);
}
document.write("Generating a random number between the range 50 and 500: ")
// Here, we are calling the JavaScript function
document.write('<strong>' + randomNumber(50, 500) + '</strong>');``````

### Output :

Generating a random number between the range 50 and 500: 494

``Math.random();``

### Example :

``````<html>
<title>Developer Helps | Javascript Random Number</title>
<body>
<h2>Javascript Random Number</h2>

Random Number between 0 and 1: <p id="random-number"></p>

<script>
document.getElementById("random-number").innerHTML = Math.random();
</script>

</body>
</html>``````

### Output :

``````Javascript Random Number

Random Number between 0 and 1:
0.2535062639322767``````

## JavaScript Random Integers

This example returns the random integer from 0 to 9.

### Example :

``````<html>
<title>Developer Helps | Javascript Random Number</title>
<body>
<h2>Javascript Random Number</h2>

Random Integer between 0 and 9: <p id="random-number"></p>

<script>
document.getElementById("random-number").innerHTML = Math.floor(Math.random() * 10);
</script>

</body>
</html>``````

### Output :

``````Javascript Random Number

Random Integer between 0 and 9:
2``````

## JS Random Function

This JavaScript function returns a random number between min (included) and max (excluded).

### Function :

``````function fetchRandomInteger(min, max)
{
return Math.floor(Math.random() * (max - min)) + min;
}``````

### Example :

``````<html>
<title>Developer Helps | Javascript Random Number</title>
<body>
<h2>Javascript Random Number</h2>
<button onclick="fetchRandomInteger(0,10)">Try Click</button><br><br>
Random Function between min and max: <p id="random-number"></p>

<script>
function fetchRandomInteger(min, max)
{
document.getElementById("random-number").innerHTML = Math.floor(Math.random() * (max - min)) + min;
}
</script>

</body>
</html>``````

### Output :

``````Javascript Random Number

Try Click

Random Function between min and max:
8``````

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