Both

Hi
yes u can do it in Both manual and automation.
But when compared with manual it's easy ,fast to do it in 
automation.

 Generally QTP is the Best to do web testing(functional).
For Performence related issues u can go for Load Runner.

Hi friends I am rajendra from Hyderabad.

Web testing in manual process is possible for only some 
testing approaches like
      Functionality testing,
      User interface testing (GUI Testing)
      Usability testing, 
      Security testing,
      Compatibility testing (browser compatibility testing -
      very imaportent in web application testing),
      Database testing
But if you want to test Performance of the website you must 
use some testing tool like WebLoad ,loadRunner.
If the application developed in java then we can use Jmeter
for testing the web application.
JMeter is a opensource freely available software from 
Apache software foundation, one can download and use it 
Without spending a single rupee.
The web application means it may have 2 tier simple 
architecture or 3 tier or n tier architecture.
If it is used 3 tier or N tier architecture then we should 
Check the performance of the system for retrieving data 
from database...etc.
Except performance testing we can conduct web testing in 
manual.
But web performance is the prime issue in web testing.

For defining approach, the very first things you need to
check  that whether this web site has static OR dynamic
pages and how many times you gone run the TEST. If you have
to do it only once then there is no point going for
Automation. If site is dynamic and will be repeatedly tested
then go for automation.
It's all about Functional Testing; for Load OR Performance
test you have to go for automated tools.

Regards,
Rupesh
+919225513854