How to Check if the Textbox Contains String in Javascript

In this tutorial, you will learn how to check if the textbox contains string in javascript. In HTML, a textbox is created using either input element or textarea element. Input element is suitable for a single line text content and textarea element is suitable for multiline text content. From a developer perspective, it can be a bit tricky to find if a textbox contains a string.

There are numerous ways to check if a textbox contains a string. But for the sake of simplicity, we will use includes() method and ternary operator (?). The includes() method is used to perform a case-sensitive search to detect whether a string contains another string or not and returns a Boolean value.

In the following example, we have one textbox where we will enter some random text. Upon click of a button, we will check if it contains a string and display the result on the screen.  Please have a look over the code example and the steps given below.


  • 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 “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">    
    <input type="text" />

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

.container {        
  text-align: center;

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

input {
display: block;
padding: 5px 10px;
margin: auto;


  • We have selected the button element, input element, and h1 element using the document.querySelector() method and stored them in btnCheck, inputEl, and output variables respectively.
  • We have attached a click event listener to the button element.
  • We have a global variable myString which holds a string "fruits" as its value.
  • In the event handler function, we are getting value from the textbox  and storing it in the value variable.
  • We are using the includes() method to verify whether value contains myString or not. If it returns true, that means value does contain myString.
  • It will always be true if the textbox contains a text that has "fruits" string in it.
  • Depending upon the result of the check, we will assign “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 inputEl = document.querySelector("input");
let output = document.querySelector("h1");

let myString = "fruits";

btnCheck.addEventListener("click", () => {
  let value = inputEl.value;
  let result = value.includes(myString) ? "Yes" : "No";
  output.innerText = result;