If I understand your question, you want to detect viewers emotional responses to web pages, either they feel happy or scared?
I think an eye tracking method will be good idea. however you need to take other logistics issues into consideration. Are you inviting them into your lab? Have you got the resources?
Better still, you can have a verbal report (which may not be accurate). Ask them how they feel about the webpages.
Thanks Emmanuel, yes almost. Actually I want to detect the emotions from the web page. What visitor feels about any thing, any topic they submit to any web page. I want to detect that emotion. One way is that I can use a DB interactive page and then I can analyse. But I don't want this. Looking for some different techniques.