May 25, 2022

How to Convert Lowercase Letters to Uppercase in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to convert lowercase letters to uppercase in javascript. Sometimes it is very important to convert the lowercase letters to uppercase letters before sending a string for further processing. From a developer perspective, it can be a bit tricky to convert lowercase letters to uppercase letters.

There are numerous ways to convert lowercase letters to uppercase letters. We are going to use the simplest approach which involves the usage of toUpperCase() method. This method will simply convert the string to an uppercase string and return a new string.

In the following example, we have one global variable that holds a string. Upon click of a button, we will convert the lowercase letters to uppercase letters 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, and h1). The div element is just a wrapper for the rest of the elements.
The innerText for the button element is “Get”.
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">

<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>Get</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 and h1 element using the document.querySelector() method and stored them in btnGet 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 as its value.
We are displaying the original string in the h1 element using the innerText property.
In the event handler function, we are calling toUpperCase() method. As a result, it will convert the lowercase letters to uppercase letters. The new string returned by this method will be stored in the result variable.
We are displaying the result in the h1 element using the innerText property.

let btnGet = document.querySelector("button");
let output = document.querySelector("h1");

let myString = "i think i just got caught up with something";

output.innerText = myString;

btnGet.addEventListener("click", () => {
  let result = myString.toUpperCase();
  output.innerText = result;
});

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