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 β 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 β
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.
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>
<head>
<title>Developer Helps | Javascript Random Number</title>
</head>
<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>
<head>
<title>Developer Helps | Javascript Random Number</title>
</head>
<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).
