The invention relates to a method for loading, storing and presenting web pages, by which means the required band widths and the time taken to load web pages for an application are reduced. The method and apparatus is achieved by the addition of a SessionDevice Extension, a Host Identification Extension, a Host Identification NAI Extension, andor a Lease Time Extension. Based on this image, brightness distributions of the discharge beam are estimated on a plurality of lines in a Z direction that are set in different positions in an X direction, and a discharge center of the beam is found from the plurality of brightness distributions. The donor layer also includes a distinct second layer coated on the first layer. An calculation part obtains a thickness of a film with high precision from the polarization state of the reflected light by using the obtained tilt angle.