trying to reference a value that is in an aspx file FROM aspx.cs file

I am having trouble referencing the value typed into the [input type="text"] box that is in the aspx file.... with my code that is in the aspx.cs file.

 the code is below:

 ASPX FILE

 <form id="frmUpdate" runat="server">

<table style="font-size:12px;font-family:Georgia;" runat="server">

<tr><td><input type Go to the complete details ...