title: When is the ctl00 prefix added?
body: <p>I have a simple asp.net page with an asp.net link button and asp.net content tag which point to a simple asp.net master page with an asp.net content place holder and a form tag. Here is the code of these two items:</p>
  
  <p>Site.Master:</p>
  
  <pre><code>&lt;%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.master.cs" Inherits="WebApplication1.SiteMaster" %&gt;
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head&gt;
      &lt;title&gt;&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;form runat="server"&gt;
              &lt;asp:ContentPlaceHolder ID="MainContent" runat="server"/&gt;
      &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Default.aspx:</p>
  
  <pre><code>&lt;%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
      CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %&gt;
  
  &lt;asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"&gt;
      &lt;asp:LinkButton ID="LinkButton1" runat="server"&gt;LinkButton&lt;/asp:LinkButton&gt;
  &lt;/asp:Content&gt;
  </code></pre>
  
  <p>For some reason when we run this simple web application on one server the id the link bhutton get is MainContent_LinkButton1
  and when we run this application on another server the id the link button get is _ctl0_MainContent_LinkButton1</p>
  
  <p>Doese someone have an idia why we get the prefix <em>ctl0</em> in a specific server and in another server we don't get it?</p>