Servlet chains have the following advantages :
* Servlet chains can be undone easily. This helps in quickly reversing the change.
* Servlet chains dynamically handle content that is created. Because of this, one can trust that all our restrictions are maintained, that the special tags are replaced, and even in the output of a servlet, all the dynamically converted PostScript images are properly displayed.
* Servlet chains cache the content for later, so it does not execute the script every time got added.
