title: This page is missing a HtmlHead control which is required for the CSS stylesheet link that is being added. Please add <head runat="server" />
body: <p>i have page and add Ajax extension but it throwing error for me</p>
  
  <p>i am using master page so this page doesn't have <code>&lt;head&gt;</code></p>
  
  <p>page code</p>
  
  <pre><code>&lt;%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %&gt;
  
  &lt;%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" runat="server" %&gt;
  
  
  &lt;asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"&gt;
  
      &lt;table style="width: 100%"&gt;
      &lt;tr&gt;
          &lt;td colspan="5" style="text-align: center; height: 20px;"&gt;Search &lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
          &lt;td style="text-align: center; height: 20px;"&gt;Ticket number&lt;/td&gt;
          &lt;td style="text-align: center; height: 20px;"&gt;Client name&lt;/td&gt;
          &lt;td style="text-align: center; height: 20px;"&gt;Address&lt;/td&gt;
          &lt;td style="text-align: center; height: 20px;"&gt;Assigned to&lt;/td&gt;
          &lt;td style="text-align: center; height: 20px;"&gt;Date&lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
          &lt;td style="width: 157px"&gt;
              &lt;asp:TextBox ID="txt_incID" runat="server" Width="146px"&gt;&lt;/asp:TextBox&gt;
          &lt;/td&gt;
          &lt;td&gt;
              &lt;asp:TextBox ID="txb_ClientName" runat="server" Width="146px"&gt;&lt;/asp:TextBox&gt;
          &lt;/td&gt;
          &lt;td&gt;
              &lt;asp:DropDownList ID="ddl_Address" runat="server" Width="146px" DataSourceID="Ds_address" DataTextField="StrName" DataValueField="StrID"&gt;
                  &lt;asp:ListItem Value="null"&gt;&lt;/asp:ListItem&gt;
              &lt;/asp:DropDownList&gt;
          &lt;/td&gt;
          &lt;td&gt;
              &lt;asp:DropDownList ID="ddl_EmpID" runat="server" Width="146px" DataSourceID="DS_Employee" DataTextField="LastName" DataValueField="EmpID"&gt;
                  &lt;asp:ListItem Value="null"&gt;&lt;/asp:ListItem&gt;
              &lt;/asp:DropDownList&gt;
          &lt;/td&gt;
          &lt;td&gt;
              &lt;asp:TextBox ID="txb_date" runat="server" Width="146px"&gt;&lt;/asp:TextBox&gt;
  
              &lt;asp:CalendarExtender ID="txb_date_CalendarExtender" runat="server" Enabled="True" TargetControlID="txb_date"&gt;
              &lt;/asp:CalendarExtender&gt;
  
          &lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
          &lt;td style="width: 157px"&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
          &lt;td style="width: 157px"&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
          &lt;td&gt;&amp;nbsp;&lt;/td&gt;
      &lt;/tr&gt;
  &lt;/table&gt;
  
      &lt;br /&gt;
      &lt;br /&gt;
      &lt;asp:SqlDataSource ID="Ds_address" runat="server" ConnectionString="&lt;%$ ConnectionStrings:TicketsConnectionString %&gt;" SelectCommand="SELECT * FROM [Streets]"&gt;&lt;/asp:SqlDataSource&gt;
      &lt;asp:SqlDataSource ID="DS_Employee" runat="server" ConnectionString="&lt;%$ ConnectionStrings:TicketsConnectionString %&gt;" SelectCommand="SELECT * FROM [Employee]"&gt;&lt;/asp:SqlDataSource&gt;
      &lt;asp:ScriptManager ID="ScriptManager1" runat="server"&gt;
      &lt;/asp:ScriptManager&gt;
  
  &lt;/asp:Content&gt;
  </code></pre>
  
  <p>in other topics people recommend add this </p>
  
  <p><code>&lt;asp:ScriptManager ID="ScriptManager1" runat="server"&gt;
      &lt;/asp:ScriptManager&gt;</code></p>
  
  <p>but I have it on my page. Any ideas how to fix?<br/>
  Master page code <br/></p>
  
  <pre><code>&lt;%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %&gt;
  
  &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"&gt;
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head&gt;
  &lt;meta name="keywords" content="" /&gt;
  &lt;meta name="description" content="" /&gt;
  &lt;meta http-equiv="content-type" content="text/html; charset=utf-8" /&gt;
  &lt;title&gt;Tickets&lt;/title&gt;
  &lt;link href="http://fonts.googleapis.com/css?family=Open+Sans:400,300,600,700|Archivo+Narrow:400,700" rel="stylesheet" type="text/css"&gt;
  &lt;link href="style.css" rel="stylesheet" type="text/css" media="screen" /&gt;
      &lt;style type="text/css"&gt;
          .Buttons
          {
              font-family: Tahoma;
              font-size: large;
              background-color: #999999;
              border-bottom-color: #FF0000;
              border-style: none none outset none;
          }
          .Logins
          {
              font-family: tahoma;
              color: #FF0000;
          }
          .ButtonsInSite
          {
              font-family: tahoma;
              background-color: #C0C0C0;
              border-color: #FFFFFF #FFFFFF #FF0000 #FFFFFF;
              border-bottom-style: double;
              border-radius: 7px;
              -moz-border-radius: 7px;
              -webkit-border-radius: 7px;
              box-shadow: 0px 2px 9px #800000;
              font-weight: bold;
          }
      &lt;/style&gt;
      &lt;/head&gt;
  &lt;body&gt;
      &lt;form id="form1" runat="server"&gt;
  &lt;div id="header-wrapper"&gt;
      &lt;div id="header"&gt;
          &lt;div id="logo"&gt;
              &lt;h1&gt;Tickets&lt;/h1&gt;
              &lt;div style="text-align: right"&gt;
  
                  &lt;asp:LoginName ID="LoginName2" runat="server" CssClass="Logins" /&gt;
                  &amp;nbsp;|
                  &lt;asp:LoginStatus ID="LoginStatus1" runat="server" CssClass="Logins" /&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  &lt;div id="wrapper"&gt; 
      &lt;!-- end #header --&gt;
      &lt;div id="page"&gt;
          &lt;div id="page-bgtop"&gt;
              &lt;div id="page-bgbtm"&gt;
                  &lt;div id="sidebar"&gt;
                      &lt;h2&gt;Navigation&lt;/h2&gt;
                      &lt;asp:Button ID="Button1" runat="server" Text="Button" Width="118px" CssClass="ButtonsInSite" /&gt;
                      &lt;br /&gt;
                      &lt;asp:Button ID="Button2" runat="server" Text="Button" Width="118px"  CssClass="ButtonsInSite"/&gt;
                      &lt;br /&gt;
                      &lt;asp:Button ID="Button3" runat="server" Text="Button" Width="118px" CssClass="ButtonsInSite"/&gt;
                      &lt;br /&gt;
                      &lt;asp:Button ID="Button4" runat="server" Text="Button" Width="118px" CssClass="ButtonsInSite"/&gt;
                      &lt;br /&gt;
                      &lt;asp:Button ID="Button5" runat="server" Text="Admin" Width="118px" CssClass="ButtonsInSite" PostBackUrl="~/Admin/AdmStart.aspx"/&gt;
                      &lt;br /&gt;
  
  
                  &lt;/div&gt;
                  &lt;!-- end #sidebar --&gt;
                  &lt;div id="content"&gt;
                      &lt;asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server"&gt;
                      &lt;/asp:ContentPlaceHolder&gt;
                  &lt;/div&gt;
                  &lt;!-- end #content --&gt;
  
                  &lt;div style="clear: both;"&gt;&amp;nbsp;&lt;/div&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
      &lt;!-- end #page --&gt; 
  &lt;/div&gt;
  &lt;div id="footer"&gt;
      &lt;p&gt; © 2013&lt;/p&gt;
  &lt;/div&gt;
  &lt;!-- end #footer --&gt;
      &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>