While testing a web application you need to consider following Cases

• Functionality Testing
• Performance Testing
• Usability Testing
• Server Side Interface
• Client Side Compatibility
• Security
Functionality:
In testing the functionality of the web sites the following should be tested:
• Links
i. Internal Links
ii. External Links
iii. Mail Links
iv. Broken Links
• Forms
i. Field validation
ii. Error message for wrong input
iii. Optional and Mandatory fields

Test  Forms are working as expected. This will include-

• Scripting checks on the form are working as expected. For example- if a user does not fill a mandatory field in a form a error message is shown.
• Check default values are being populated
• Once submitted , the data in the forms is submitted to a live database or is linked to an working email address
• Forms are optimally formatted for better readability

• Database
* Testing will be done on the database integrity.
• Cookies
* Testing will be done on the client system side, on the temporary Internet files.
Test Cookies are working as expected. Cookies are small files used by websites to primarily remember active user sessions so you do not to log in every time you visit a website. Cookie Testing will include

• Testing cookies (sessions) are deleted either when cache is cleared or when they reach their expiry.
• Delete cookies (sessions) and test that login credentials are asked for when you next visit the site.

Performance :
Performance testing can be applied to understand the web site’s scalability, or to benchmark the performance in the environment of third party products such as servers and middleware for potential purchase.
• Connection Speed:
Tested over various networks like Dial Up, ISDN etc
• Load:
i. What is the no. of users per time?
ii. Check for peak loads and how system behaves
iii. Large amount of data accessed by user
• Stress:
i. Continuous Load
ii. Performance of memory, CPU, file handling etc..
Usability:
Usability testing is the process by which the human-computer interaction characteristics of a system are measured, and weaknesses are identified for correction.
• Ease of learning
• Navigation
• Subjective user satisfaction
• General appearance
Server Side Interface:
In web testing the server side interface should be tested. This is done by verify that communication is done properly. Compatibility of server with software, hardware, network and database should be tested.
Client Side Compatibility:
The client side compatibility is also tested in various platforms, using various browsers etc.
Security:
The primary reason for testing the security of a web is to identify potential vulnerabilities and subsequently repair them.
• Network Scanning
• Vulnerability Scanning
• Password Cracking
• Log Review
• Integrity Checkers
• Virus Detection