Being a PHP guy myself I recently had to write a spider to an asp.net site. I was really surprised by the different approach to ajax and form-handling.

For example, in the PHP sites I've worked with, a deletion of a database entry would be something like:

GET delete.php?id=&confirm=yes

In this asp.net application you would instead post a form, including all inputs on the page, with a huge __VIEWSTATE and __EVENTVALIDATION. This would be more than 10 times as big as above.

The reply would be the complete side again, with a footer containing some structured data for javascript to parse and display the result. Again, the whole page is sent, and then throwed away(?) since it's already displayed. Why not just send the footer with the data to parse (it's not json nor xml but a | separated list).

I really can't see why you would design a system that way. Usually you've a fast client, and a somewhat fast server but a really slow connection. Why not keep the datatransfer to a minimum? Why those huge __VIEWSTATE and __EVENTVALIDATION?

It seems that everything is done way to chatty and way to complicated. I really can't see the point and that usually means that I'm missing something. So please tell me, what are the reasons for this design and what benefits (and weaknesses) does it have?

(Yes I know that __VIEWSTATE is used to tell what type of form-konfiguration should be sent back to the server. But WHY is this needed?)

Please keep this discussion strictly technical and avoid flamewars.

Update:

Please excuse the somewhat rantish question. I tried to explain my view to be able to get a better answer. I am not saying that asp.net is bad, I am saying that I don't understand the meaning of those concepts. Usually that means that I've things to learn instead of the concepts beeing wrong.

I appreciate the explanations about that "you don't have to do this way in asp.net", I'll read up on MVC and other .net technologies. However, there most be a reason for this site (the one I referred to) to be written the way it is. It's written by professionals for a big organisation with far more experience than what I've. Any explanation about their (possible) design choice would be welcome.