Javascript String toLowerCase()

In this tutorial, we will learn about the JavaScript String toLowerCase() method with the help of examples.

The toLowerCase() method returns the string converted to lowercase.


const message = "JAVASCRIPT IS FUN";

// convert message to lowercase const lowerMessage = message.toLowerCase();
console.log(lowerMessage); // Output: javascript is fun

toLowerCase() Syntax

The syntax of the toLowerCase() method is:


Here, str is a string.

toLowerCase() Parameters

The toLowerCase() method does not take in any parameters.

toLowerCase() Return Value

  • Returns a new string representing the calling string converted to lowercase.


  • The toLowerCase() method raises TypeError when called on null or undefined.
  • The toLowerCase() method does not change the original string.

Example: Using toLowerCase() method

let str = "Hello World!";
let sentence = "Java is to JavaScript what Car is to Carpet.";

let lowercase_str = str.toLowerCase();
console.log(lowercase_str); // hello world!
let lowercase = sentence.toLowerCase();
console.log(lowercase); // java is to javascript what car is to carpet.


hello world!
java is to javascript what car is to carpet.

Recommended Reading: JavaScript String toUpperCase()

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