When a form is submitted in classic ASP, all form values are
cleared. Suppose you have submitted a form with a lot of
information and the server comes back with an error. You
will have to go back to the form and correct the
information. You click the back button, and what
happens.......ALL form values are CLEARED, and you will have
to start all over again! The site did not maintain your
ViewState.

When a form is submitted in ASP .NET, the form reappears in
the browser window together with all form values. How come?
This is because ASP .NET maintains your ViewState. The
ViewState indicates the status of the page when submitted to
the server. The status is defined through a hidden field
placed on each page with a <form runat="server"> control.
The source could look something like this:

<form name="_ctl0" method="post" action="page.aspx" id="_ctl0">
<input type="hidden" name="__VIEWSTATE"
value="dDwtNTI0ODU5MDE1Ozs+ZBCF2ryjMpeVgUrY2eTj79HNl4Q=" />

.....some code

</form>

View State is nothing but to store peace of information 
in the form of hidden field

Yes. It is Possible For Whole Page is Saved In View State