toLowerCase Examples

The general syntax for this method is:

stringName.toLowerCase();

This method returns a copy of stringName with all uppercase letters replaced by their lowercase counterparts. It leaves non-alphabetic characters unchanged.

"LaunchCode".toLowerCase();

Output

launchcode

Example

The domain portion of an email address (the portion after the @ symbol) is case-insensitive. Emails with domain launchcode.org are the same as those with domain LAUNCHCODE.ORG. By convention, the all-lowercase version is typically used by an application.

This program standardizes an email address by converting it to all lowercase characters.

let input = "[email protected]";
let email = input.toLowerCase();
console.log(email);

Output

[email protected]

Warning

This example is a bit crude, since the portion of an email address before the @ symbol is allowed to be case-sensitive. When standardizing the case of an email in a real application, we would want to be more precise and only convert the domain portion to lowercase characters.