How to Check if String Starts with Vowel in Javascript

In this tutorial, you will learn how to check if string starts with vowel in javascript. In the English alphabet, we have vowels and consonants. A vowel is a sound that is represented by letters such as a, e, i, o, and u. For a newbie developer, it can be a bit tricky to find if a string starts with a vowel.

There are numerous ways to check if a string starts with a vowel. But for the sake of simplicity, we will use the includes() method, toLowerCase() method, charAt() method, and ternary operator (?) to accomplish our goal. The toLowerCase() method converts all letters in a string to lowercase.

A string consists of multiple characters and these characters in a string have a 0-based index. That means the first character in a string has an index of 0 and to get that character by index, we can use charAt() method. 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 global variable that holds a string. Upon click of a button, we will check if the string starts with a vowel 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 attached a click event listener to the button element.
  • We have two variables, myString which holds a string as its value and vowels which holds only vowel characters.
  • In the event handler function, we are calling includes() method and passing the first character of the string in a lowercase.
  • We are using charAt() method and passing 0 as a parameter to get the first character of the string.
  • We are using toLowerCase() method to convert first character into a lowercase.
  • The includes() will return a Boolean value which we are storing in the found variable.
  • We are using the ternary operator (?) and checking whether found is true or false. If it is true, that means the string starts with a vowel.
  • 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 output = document.querySelector("h1");

let myString = "All is well";
let vowels = "aeiou";

btnCheck.addEventListener("click", () => {

  let found = vowels.includes(myString.charAt(0).toLowerCase())
  let result = found ? "Yes" : "No";
  output.innerText = result;