toUpperCase() in JavaScript – How to Convert String to Uppercase
Whenever you use toUpperCase() on a string, the method does the following:
- It converts its calling string to uppercase.
- 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
toUpperCase()
. So, in"Hello, World!".toUpperCase()
,"Hello, World!"
is the calling string. toUpperCase()
is sometimes written asString.prototype.toUpperCase()
because it is a method of theString
object'sprototype
property.
Syntax of the toUpperCase()
Method
Here is toUpperCase()
's syntax:
callingString.toUpperCase();
The snippet above shows that toUpperCase()
does not accept any argument.
Example 1: Convert CodeSweetly
to Uppercase
"CodeSweetly".toUpperCase();
// The invocation above will return: "CODESWEETLY"
Example 2: Convert a JavaScript String to Uppercase
"friday, my friend, was born on friday".toUpperCase();
// The invocation above will return: "FRIDAY, MY FRIEND, WAS BORN ON FRIDAY"
tip
To convert a JavaScript string to lowercase, use toLowerCase()
.
Overview
toUpperCase()
returns the uppercase version of its calling string.