How to Trim Decimals in Javascript
In this tutorial, you will learn how to trim decimals in javascript. There are times when we only care about the whole number and not the decimal part of the number, even if the decimal representation of the number provides an exact value. From a developer perspective, it can be a bit tricky to trim decimals from a number.
There are numerous ways to trim decimals from a number. We are going to use the simplest approach which involves the usage of the Math
object. This object contains trunc()
method which removes the decimal part and returns the integer part of a number.
In the following example, we have one global variable that holds a decimal number. Upon click of a button, we will trim decimals from the number and display the result on the screen. Please have a look over the code example and the steps given below.
HTML & CSS
- We have 3 elements in the HTML file (
div
,button
, andh1
). Thediv
element is just a wrapper for the rest of the elements. - The
innerText
for thebutton
element is“Remove”
. - 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"> <button>Remove</button> <h1>Result</h1> </div> <script src="script.js"></script> </body> </html>
.container { text-align: center; } button { margin-top: 10px; padding: 10px 20px; }
Javascript
- We have selected the
button
element andh1
element using thedocument.querySelector()
method and stored them inbtnRemove
andoutput
variables respectively. - We have attached a
click
event listener to thebutton
element. - We have a global variable
myNum
which holds a decimal number as its value. - We are displaying the original number in the
h1
element using theinnerText
property. - In the event handler function, we are calling
trunc()
method of Math object and passingmyNum
as a parameter. As a result, it will trim decimals from the number and will return the integer part. - The returned value is stored in the
result
variable. - We are displaying the
result
in theh1
element using theinnerText
property.
let btnRemove = document.querySelector("button"); let output = document.querySelector("h1"); let myNum= 1214.101200; output.innerText = myNum; btnRemove.addEventListener("click", () => { let result = Math.trunc(myNum); output.innerText = result; });