You guys are both right, you may or not need to use InterDev to develop ASP applications.
It mainly depends on which functionalities you want in Your pages.
Adding lines of server-side code or client side code to an ASP page could be simply done using notepad or a common text editor and it would work fine (as long as your web server understands VBscript or Jscript).
The problem might arise if you want to use PageObjects or similar in you pages. In this case you want to use InterDev for the intrinsic hidden code it writes in your page when you add them. In my experience, it is almost impossible to maintain such a page with notepad.
I use PHP and I'm quite comfortable with it.
ASP is slow, and for big projects it can become a "nasty guest".
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