A Web server storing a Java program for generating an HTML file of a Web page includes a portion for obtaining an HTML file, a first conversion portion for converting the file into Java codes, a portion for replacing the codes with a part of a Java program related to the Web page structure, the Java program being for generating the HTML file, a portion for extracting Java codes of a part related to a designated Web page structure, a second conversion portion for converting the codes into an HTML file, and a portion for transmitting the file to the terminal device. If the HTML file contains a tag indicating an unmodifiable part, the first conversion portion converts the tag into a Java code indicating an unmodifiable part. The second conversion portion converts the code contained in the Java codes into the tag.