Function Updated 17 Oct 2026
String.toUpperCase()
Returns the string converted to upper case. Letters such as æ, ø and å are converted too. toLocaleUpperCase() gives the same result.
See also String.toLowerCase
Parameters
This function takes no parameters.
Returns
A new string in upper case.
Example
Normal JavaScript, running in the browser or on the Docly™ server.
write("Hello world".toUpperCase()); // HELLO WORLD
write("\n");
write("æøå".toUpperCase()); // ÆØÅThe JavaScript above produces this output:
HELLO WORLD
ÆØÅ