How to Check if String has Trailing Whitespace in Javascript

In this tutorial, you will learn how to check if string has trailing whitespace in javascript. It is pretty common to get an extra unwanted trailing whitespace in a sentence. For a newbie developer, it can be a bit tricky to find if a string has a trailing whitespace.

There are numerous ways to check if a string has a trailing whitespace. But for the sake of simplicity, we will use length property and trimEnd() method. The length property returns the length of the string. If the string is empty, then it will return 0. The trimEnd() method removes any whitespace at the end of a string.

In the following example, we have one global variable that holds a string. Upon click of a button, we will check if the string has a trailing whitespace and display the result on the screen.  Please have a look over the code example and the steps given below.


  • We have 3 elements in the HTML file (div, button, and h1). The div element is just a wrapper for the rest of the elements.
  • The innerText for the button element is “Check” 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">

  <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">


  <div class="container">    

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

.container {        
    text-align: center;

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


  • We have selected the button element and h1 element using the document.querySelector() method and stored them in btnCheck and output variables respectively.
  • We have a global variable myString which holds a string as its value.
  • We have attached a click event listener to the button element.
  • In the event handler function, we are using the length property to get the existing length of the string. We are also getting length after removing any trailing whitespace using trimEnd() method. If both the lengths are  not equal, that means the string has a trailing whitespace.
  • Depending upon the result of the check, we are assigning "Yes" or "No" to the result variable.
  • We are displaying the result in the h1 element using the innerText property.
let btnCheck = document.querySelector("button");
let output = document.querySelector("h1");

let myString = `There is some trailing whitespace               `;

btnCheck.addEventListener("click", () => {  
  let result = myString.length !== myString.trimEnd().length ? "Yes" : "No";
  output.innerText = result;