Its a big challange to test a web site. Visit the following 
link for more details:

http://quality-assurance-software-
testing.blogspot.com/2005/08/web-applications-testing.html

The following are the tests need to be done for Web 
application.


Static Testing
Dynamic Testing
Navigation Testing
Compatabilty Testing
Functionality Testing
Link Testing

for an web application we need 2 check

URL of appl
navigation(Normal links,broken links_
scalability
reliabilty(recovery testing)
usability
compatbility
forms,cookies

for web application mainly tests as follows 

userinterface means everyone understand the application is 
mportant 
funcationality 
navigation
performence means speed of acces is imp
links

Functional Testing
Smoke Testing(for UI and API's-- Through Automation tool)
Regression Testing
Batch Process Testing(for simulators)

Performance Testing also

1)the imp once r firstly we'll check for the UI with GUI
testing whether font, colour of backround& fonts r easily
understandable.
2)then for checking the functionality of each objects in
application we'll do functionalty testing
3) to check for then hyperlinking we'll do navigation testing
4) to check for load/volume/sress on the application we'll
do performance testing

1)Functionality testing
2)security
3)Performance
4)Link testing
5)Regression testing
Below are optional depends on project
8)Comptability

1,Functionslity Testing.
2,Security Testing ( XSS testing,HTTP vulnerable 
testing,Script Injection).
3,Browser Copatibility Testing.
4,Sanity Testing.
5,Load/Performance Testing.