How to Get the Absolute Value of a Number in Javascript
In this tutorial, you will learn how to get the absolute value of a number in javascript. Absolute value is measured based on the distance from zero that a number is on the number line, without taking direction in consideration.
In layman terms, the value that you get after removing any negative sign in front of a number is known as an absolute value. For example, 1 is the absolute value of -1.
Getting absolute value is very easy, but it can be tricky if the number is coming from an input field because the value present in the input field is of string type. So first, we have to convert it into a number type using the Number()
method and then perform any sort of calculations.
To get the absolute value of any number, we can make use of the Math
object. This object contains a lot of methods and properties which can help us in various mathematical operations. One of those methods is the abs()
method.
In the following example, we have an input field in which we will enter a random number. Upon click of a button, we will get the absolute value 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
, andh1
). Thediv
element is just a wrapper for the rest of the elements. - The
innerText
for thebutton
element is“Get”
and for theh1
element, it is“Result”
. - We have done some basic styling using CSS and added the link to our
style.css
stylesheet inside thehead
element. - We have also included our javascript file
script.js
with ascript
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" placeholder="Enter Number"> <button>Get</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 the
input
element,button
element, andh1
element using thedocument.querySelector()
method and stored them ininput
,btnGet
, andoutput
variables respectively. - We have attached a
click
event listener to thebutton
element. - In the event handler function, we are passing the value of the
input
element to theNumber()
method and storing the number in thenum
variable. - We are calling the
abs()
method to get the absolute ofnum
and storing it in theresult
variable. - We are displaying the
result
in theh1
element using theinnerText
property.
let input = document.querySelector("input"); let btnGet = document.querySelector("button"); let output = document.querySelector("h1"); btnGet.addEventListener("click", () => { let num = Number(input.value); let result = Math.abs(num); output.innerText = result; });