By the way, I can not use a JavaScript based solution.

What's wrong with the back button on the user's browser?

You'll need to pass the relevant parameters on the url they click to view
the detail page. eg;

detail.aspx?ID=123&colour=green&minprice=100

or whatever fields you use.  Grab that info and add it to the "Back" link;

search.aspx?colour=green&minprice=100

Then your search.aspx page will use the values from the querystring if they
are present and use them to pre-populate the form and search for results.

Someone else may have something more elegant.

One pattern to try is setting up the form and details in two panels on the
same page. This is a very simple MVC like pattern. Hide the panel not in use
at the time (or not - as showing the search still works). You can refine
this with things like the AJAX collapsing panel (accordian panel? forget the
name) and have the form hide and show based on use action. As all is on one
page, you can keep state for the controls.

To do this on more than one page, you will have to build the engine that
stores the state.

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