Getting a specific xml tag value with php [closed]

[Unimatrix]

I got a script i made. It is like a chatbot.I want to ask how would i get a specific xml tag value with php.Here is the xml\[code\]<pattern>Hello</pattern><template><random><li>Hi there.</li><li>Hey.</li><li>Hello at you too.</li></random></template><pattern>Hi</pattern><template><random><li>Hi there.</li><li>Hey.</li><li>Hello at you too.</li></random></template>\[/code\]So i would like to have the user input a message and php checks the xml file for the pattern tag that is same to the user input.How could i do that?. I am using AIML.I'm sorry if i am not specific enough.