Determine the black hat jump code (js and php versions) of spider code based on the user-agent _ javascript skills

This article mainly introduces how to determine the black hat jump code (js version and php version) of the spider code based on the user-agent ), if you need a friend, you can refer to the black hat seo technique and use it to determine the user-agent of the client browser on the server and perform further operations,

Someone has been using this code on the Internet for a long time. first, a js code is used to determine the visitor's path. if it is a search engine, the code jumps. if it is a direct access, the code remains unchanged. it has been found online for a long time. thanks to the original author