December 1, 2021

How to Get Remainder of Division in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to get remainder of division in javascript. The remainder of a division is also known as modulus. The division is one of the basic arithmetic operations which every newbie developer should be able to perform without any issue. But it can also be tricky if you are trying to do the division with 2 numbers that are coming from 2 different input fields.

Almost in every programming language, we have a modulus operator (%) to get the remainder of the division and it is also present in javascript. But since the value present in the input field is of string type, we have to convert it into number type using the Number() method and then do the calculation using modulus operator (%).

In the following example, we have 2 input fields in which we will enter 2 random numbers. Upon click of a button, we will get the remainder of the division and display that on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 4 elements in the HTML file (div, input, button, and h1). The div element is just a wrapper for the rest of the elements.
The innerText for the button element is “Modulus” and for the h1 element, it is “Result”.

We have done some basic styling using CSS and added the link to our style.css stylesheet inside the head element.
We have also included our javascript file script.js with a script tag at the bottom.

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <link rel="stylesheet" href="style.css">
  <title>Document</title>
</head>
<body>
  
  <div class="container">
    <input type="number" id="firstInput" placeholder="Enter Numerator">    
    <input type="number" id="secondInput" placeholder="Enter Denominator">    
    <button>Modulus</button>
    <h1>Result</h1>
  </div>

  <script src="script.js"></script>
</body>
</html>

.container {        
    text-align: center;
}

button {
  margin-top: 10px;
  padding: 10px 20px;
}

input {
  display: block;  
  margin: 10px auto;
  padding: 10px 20px;
}

input[type=number]::-webkit-inner-spin-button, 
input[type=number]::-webkit-outer-spin-button { 
  -webkit-appearance: none; 
  margin: 0; 
}

Javascript

We have selected both the input elements, button element, and h1 element using the document.querySelector() method and stored them in firstInput, secondInput, btnModulus, and output variables respectively.
We have attached a click event listener to the button element.
In the event handler function, we are passing values of both the input elements to the Number() method and performing the calculation using the modulus operator (%). The result is stored in the result variable.

We are displaying the result in the h1 element using the innerText property.

let firstInput = document.querySelector('#firstInput');
let secondInput = document.querySelector('#secondInput');
let btnModulus = document.querySelector('button');
let output = document.querySelector('h1');


btnModulus.addEventListener('click', () =>{
    let result = Number(firstInput.value) % Number(secondInput.value);        
    output.innerText = result;    
});

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