How to convert JavaScript characters to uppercase and lowercase

Explains how to convert a string to uppercase or lowercase in JavaScript.

How can I convert a string to uppercase or lowercase?

There are toUpperCase and toLowerCase methods.
These can be used to convert strings to uppercase or lowercase respectively.

Convert string to uppercase or lowercase

toUpperCase converts a string to uppercase

To convert a string to uppercase, use the toUpperCase method.

string.toUpperCase();

This method converts all characters in a string to uppercase.
For example, to convert the string “javascript” to uppercase:

let str = "javascript";
let result = str.toUpperCase();
console.log(result); // "JAVASCRIPT"

toLowerCase converts a string to lowercase

To convert a string to lowercase, use the toLowerCase method.

string.toLowerCase();

This method converts all characters in a string to lowercase.
For example, to convert the string “JAVASCRIPT” to lowercase:

let str = "JAVASCRIPT";
let result = str.toLowerCase();
console.log(result); // "javascript"

Summary of “How to convert letters to uppercase and lowercase”

The following is a summary of how to convert characters to uppercase and lowercase.

Now you know how to convert using toUpperCase and toLowerCase!

Before converting a string, it is a good idea to perform a null check to avoid errors if the string is null or undefined.