Gets a command to change the underline formatting of characters in a selected range.
readonly changeFontUnderline: ChangeFontUnderlineCommand
A ChangeFontUnderlineCommand object that provides methods for executing the command and checking its state.
You can invoke this command by calling the execute method.
The execute method checks the command state (obtained using the getState method) before executing, and decides whether the action can be performed. The execute and getState methods are members of the ChangeFontUnderlineCommand class.
This command applies settings to all characters in the selection. If it is collapsed (the selected range's length equals 0) - the settings are applied to the nearest word.