JavaScript String toLowerCase() Method
The JavaScript toLowerCase() method converts all characters in a string to lowercase, returning a new string without modifying the original.
It’s commonly used for case-insensitive comparisons, standardizing text input, or formatting strings by ensuring all characters are in lowercase.
Syntax:
str.toLowerCase();Return value:
This method returns a new string in which all the upper-case letters are converted to lowercase.
Example 1: Converting all characters of a string to lowercase
The toLowerCase() method converts all characters in the string ‘GEEKSFORGEEKS’ to lowercase. The resulting string ‘geeksforgeeks’ is then logged to the console.
let str = 'GEEKSFORGEEKS';
// Convert to lowercase
let string = str.toLowerCase();
console.log(string);
Output
geeksforgeeks
Example 2: Converting elements of array to lowercase
The code uses the map() method to create a new array where each element is converted to lowercase using the toLowerCase() method. The resulting array is [‘javascript’, ‘html’, ‘css’], which is then logged to the console.
let languages = ['JAVASCRIPT', 'HTML', 'CSS'];
let result = languages.map(lang => lang.toLowerCase());
console.log(result);
Output
[ 'javascript', 'html', 'css' ]
We have a complete list of Javascript string methods, to check those please go through this Javascript String Complete reference article.
Supported Browsers:
JavaScript String toLowerCase() Method- FAQs
Does toLowerCase() modify the original string?
No, toLowerCase() returns a new string and does not change the original string.
Can toLowerCase() handle special characters and numbers?
Yes, toLowerCase() only affects alphabetic characters; numbers and special characters remain unchanged.
Is toLowerCase() case-sensitive?
toLowerCase() is not case-sensitive; it converts all uppercase characters to lowercase.
Can I use toLowerCase() on non-string values?
toLowerCase() can only be used on strings. Using it on other data types will result in a TypeError.
Does toLowerCase() support Unicode characters?
Yes, toLowerCase() supports Unicode characters, converting them to their corresponding lowercase forms if available.
