webserver  :
1)webserver imlementation on servlet,jsp Api specifation.
2)less middleware services
3)its recoginses only WAR files
4}its understand only http requset
5}its develop only webapplications.
Ex: tomcat server
Applicationserver:
1)Application server implementation on All J2EE specifications
2)more middle ware services( nearly 16 middle ware)
 Ex:connection pooling,security,transaction management
3)its recoginses  WAR,RAR,EAR files
4)its understand http,non http requsets
5}its develop  webapplications and enterpraise
applications,distributed applications.
ex:-weblogic

FORMULA:
APPLICTION SERVER=WEBSERVER+MIDDLEWARE SERVERICE+EJB CONTAINER