toLowerCase() in JavaScript – How to Convert String to Lowercase

Whenever you use toLowerCase() on a string, the method does the following:

1. It converts its calling string to lowercase.
2. It returns the new version of the calling string—without changing the original string.

Note

• A calling string is a string on which you used toLowerCase(). So, in "Hello, World!".toLowerCase(), "Hello, World!" is the calling string.
• toLowerCase() is sometimes written as String.prototype.toLowerCase() because it is a method of the String object’s prototype property.

Use the toLowerCase() method to convert your string to lowercase.

Syntax of the toLowerCase() Method

toLowerCase() does not accept any argument. Here is the syntax:

callingString.toLowerCase();

Example 1: Convert CodeSweetly to Lowercase

"CodeSweetly".toLowerCase();

// The invocation above will return: "codesweetly"

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Example 2: Convert a JavaScript String to Lowercase

"FRIDAY, MY FRIEND, WAS BORN ON FRIDAY".toLowerCase();

// The invocation above will return: "friday, my friend, was born on friday"

Try Editing It

Tip

To convert a string to uppercase, use toUpperCase().