Formats any additional data that should be appended to the field. Any '%id' entities in the formatted string are replaced with the field's id. Any '%name' entities in the formatted string are replaced with the field's name.
Sets one of the firleds attributes. If the attribute does not exist then it is created. The attributes 'id', 'name' and 'value' can not be modified throught this function.
Overrides Field::getAsHtml() (Returns the (X)HTML representation of the field. This function should be concidered as an abstract function, any subclasses should override this.)