How to Append Variable Value to String in Javascript

In this tutorial, you will learn how to append variable value to string in javascript. Any grouping of letters, numbers, punctuation, special characters, etc. is referred to as a text string. The numbers vary from 0 to 9, but we must combine several small numbers to create larger ones. For a newbie developer, it can be a bit tricky to append a variable value to a string.

There are numerous ways to append a variable value to a string. But for the sake of simplicity, we will make use of template string which helps in creating a dynamic string by using variables in it.

In the following example, we have two global variables, one is holding a number and another one a string. Upon click of a button, we will append a variable value to a string 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 (divbutton, and h1). The div element is just a wrapper for the rest of the elements.
  • The innerText for the button element is “Add” 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 btnAdd and output variables respectively.
  • We have two global variables name and age where one variable holds a string and another one a number.
  • We have attached a click event listener to the button element.
  • In the event handler function, we are creating a string dynamically where we we are using global variables name and age .
  • We are storing the final string in the result variable.
  • We are displaying the result in the h1 element using the innerText property.
let btnAdd = document.querySelector("button");
let output = document.querySelector("h1");

let name = "Nelson";
let age = 73;
btnAdd.addEventListener("click", () => {  
  let result = `${name} is ${age} years old`;
  output.innerText = result;