modularization program design,use parameter very facility.all asp code can liberty modify,no encrypt.no use and time restrict.class setting convenient,no restrict class.can add word file.have user browse deduction point and period of validity function.safety very excellence,prevent SQL attack,prevent database download,prevent espionage program,no back door code .design system use new Antivirus,ensure program no virus.page modify easy,use DreamweaverFrontPage modify page.much Website use our program,contact Webmaster know other user Website.