Parameter syntax:
lower | upper | capital
If there is a text selection, this command converts the character case of this selection. If one or more nodes are selected, this command converts the character case of all the text contained in these nodes. If there is no selection of any kind, this command converts the character case from caret position to end of word, then it moves the caret to the next word.
All characters are converted to lowercase characters.
All characters are converted to uppercase characters.
First character of a word is converted to an uppercase character. The other characters are converted to lowercase characters.