JavaScript - convert string to uppercase

In this article, we would like to show you how to convert string to upper case in JavaScript.

The string class contains two methods that help to make the conversion to upper case. One of them allows making conversion by taking into account locale. To see practical usage of methods look at the below examples.

1. Built-in conversion approach example

This section shows how to convert any string to upper case taking into account locale. In almost all cases it produces a similar output string to the version without locale.

// ONLINE-RUNNER:browser;

var text = 'Hi! How are you?';
var convertedText = text.toUpperCase();

console.log(convertedText);

Output:

HI! HOW ARE YOU?

2. Built-in conversion approach with locale example

This section shows how to convert any string to upper case taking into account locale. In almost all cases it produces a similar output string to the version without locale.

// ONLINE-RUNNER:browser;

var text = 'Здравствуй! Как поживаете?';

var convertedText = text.toLocaleUpperCase();
//var convertedText = text.toLocaleUpperCase('ru-RU');
//var convertedText = text.toLocaleUpperCase(['ru-RU', 'en-US']);

console.log(convertedText);

Output:

ЗДРАВСТВУЙ! КАК ПОЖИВАЕТЕ?