Web application projects

I have a little assignment where I have to make some changes to a Web
Application Project, and there are some basic information I have spent
lots of time figuring out, So you can really make me happy if you can
help me find the problem.

The problem is that I have to make some changes to the start page. The
strange thing is that when I write some new code in the aspx file and
build the site the changes I made to the Axpx file doesnt show on the
final HTML page.

Just to make sure I added this line into the aspx file.

<div style ="z-index:999999999; postion:absolute;  top: 100px; left:
100px;>Is this text visible to anybody?</div>

when the page is built I tried to locate the new div tag. Even when I
look at the page source I cant find the new HTML.

The project uses masterpages.

another funny thing is that the start page hasnt got any body or head
tags, but in spite of this it works fine.

Any help will be appreciated.

Bjarke