title: Ajax Extension Works With Master Page But Not With Content Page
body: <p>I have Installed Ajax Extension and added reference to the application. I am facing very strange problem that my master page accept the Ajax Extension Tools where as my content page throw error like “Element ScriptManager/UpdatePanel is not a known Element."</p>
  
  <pre><code>My WebConfig:
  &lt;?xml version="1.0"?&gt;&lt;configuration&gt;
  
    &lt;system.web&gt;
    &lt;customErrors mode="Off"&gt;
  
    &lt;/customErrors&gt;
      &lt;authentication mode="Windows"/&gt;
    &lt;pages&gt;
      &lt;controls&gt;
        &lt;add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/&gt;
      &lt;/controls&gt;
    &lt;/pages&gt;
  
    &lt;/system.web&gt;
    &lt;/configuration&gt;
  
  
  My contentPage:
  &lt;%@ Page Language="C#"  MasterPageFile="~/yuva.master" AutoEventWireup="true"   CodeBehind="PicSave.aspx.cs" Inherits="YuvaRK12.PicSave" %&gt;
  
  
   &lt;asp:Content ID="MypicSave" runat="server"  ContentPlaceHolderID= "MainCPH" &gt;
   &lt;table id="Main" style="width:100%; height:350px; background-color:White;"&gt;&lt;tr&gt;&lt;td&gt;
  
   &lt;asp:Label ID="lbl1" runat="server"&gt;&lt;/asp:Label&gt;
   &lt;asp:Label ID="vis" runat="server" &gt;&lt;/asp:Label&gt;
  
     &lt;table id="Photo" style=" margin-left:auto; margin-right:auto;"&gt;
     &lt;tr&gt;&lt;td&gt;
           &lt;asp:FileUpload ID="FileUpload1" runat="server"  /&gt;
  
     &lt;/td&gt;&lt;/tr&gt;
     &lt;tr&gt;&lt;td&gt;
  
         &lt;input  id="ImageBT"  
                 type="button" 
                 value="Upload Image" 
                 runat="server" 
                 onserverclick="ImageBT_ServerClick" style=" float:left;" /&gt;
  
     &lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="border-style:ridge;  border-width:3px;"&gt;
     &lt;center&gt;
  
           &lt;asp:Image id="MyImg" runat="server" 
                      style="width:150px; 
                      height:150px;"  
                      BorderStyle="solid" 
                      BorderWidth="1px"/&gt;
     &lt;/center&gt;
     &lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;  &lt;!-- Photo End Here--&gt;
  
      &lt;center&gt;
      &lt;table&gt;&lt;tr&gt;&lt;td&gt;
       &lt;asp:Button ID="SBtn" runat="server" 
                   Text="Submit" BorderStyle="ridge"  
                   BorderWidth="4px" 
                   OnClick="SBtn_Click" /&gt;
     &lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;
     &lt;/center&gt;
  
     &lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;!--Main End here--&gt;
     &lt;/asp:Content&gt;
  </code></pre>
  
  <p>What I am missing here?. Very strange Ajax Extension is working with master page but not with content page!. What is the solution of it?.</p>