Web Shell Detector is a Web-based tool for identifying PHP shells. Besides PHP, it can also detect Perl CGI, ASP and ASPX shells. It is packed with the script is a file signature database for identifying known shell files. When a suspicious file is detected, the user has the option to submit it for analysis. To access the default installation, ...

An emulator for ASP in PHP,SO you can write such code as "$response->write("hello world");" in PHP.