$compareAttribute public property
The name of the attribute to be compared with. When both this property and $compareValue are set, the latter takes precedence. If neither is set, it assumes the comparison is against another attribute whose name is formed by appending '_repeat' to the attribute being validated. For example, if 'password' is being validated, then the attribute to be compared would be 'password_repeat'. See also $compareValue.
public string $compareAttribute = null