MultiHandleSliderExtender not working in master child page

hello every i am working with MultiHandleSliderExtender for bind price range .

when i coded for simple page (without aattached master page ) working fine but when i using in master child page then it is not working .

please suggest me anyone 

my code is 

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default4.aspx.cs" Inherits="Default4" %><%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %><asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"></asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"><title></title><style type="text/css">
        body
        {
            font-family: Arial;
            font-size: 10pt;
            margin: 0;
            padding: 0;
        }
        .loader
        {
            height: 50px;
            width: 100px;
        }
        .item
        {
            width: 202px;
            border: 1px solid #ccc;
            box-shadow: 2px 2px 8px 2px #ccc;
        }
        .item .header
        {
            height: 30px;
            background-color: #9F9F9F;
            color: #fff;
        }
        .item .body
        {
            width: 200px;
            height: 200px;
        }
        .item .image
        {
            height: 200px;
            width: 200px;
        }
        .item .footer
        {
            height: 50px;
        }
        .button, .button:hover
        {
            height: 45px;
            padding: 10px;
            color: White;
            line-height: 23px;
            text-align: center;
            font-weight: bold;
            cursor: pointer;
            border-radius: 4px;
            text-decoration: none;
            background-color: #9F9F9F;
            border: 1px solid #5C5C5C;
        }
        #price_slider, #price_slider_value
        {
            width: 400px;
            margin: 5px;
        }
        #empty
        {
            display: block;
            width: 400px;
            background-color: #9F9F9F;
            color: #fff;
            height: 30px;
            line-height: 30px;
            margin: 5px;
            text-align: center;
        }
        .modal
        {
            position: fixed;
            z-index: 999;
            height: 100%;
            width: 100%;
            top: 0;
            background-color: Black;
            filter: alpha(opacity=60);
            opacity: 0.6;
            -moz-opacity: 0.8;
        }
        .center
        {
            z-index: 1000;
            margin: 300px auto;
            padding: 10px;
            width: 130px;
            background-color: White;
            border-radius: 10px;
            filter: alpha(opacity=100);
            opacity: 1;
            -moz-opacity: 1;
        }
        .center img
        {
            height: 128px;
            width: 128px;
        }</style><asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"   EnablePartialRendering="true"></asp:ToolkitScriptManager><asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1"><ProgressTemplate><div class="modal"><div class="center"><img alt="" src="loader.gif" /></div></div></ProgressTemplate></asp:UpdateProgress><asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><asp:MultiHandleSliderExtender ID="MultiHandleSliderExtender1" runat="server" TargetControlID="txtSlider"
                Minimum="1" Maximum="1000" Increment="1" RaiseChangeOnlyOnMouseUp="true" EnableRailClick="false"
                OnClientDragEnd="OnClientDragEnd"><MultiHandleSliderTargets><asp:MultiHandleSliderTarget ControlID="hfStart" /><asp:MultiHandleSliderTarget ControlID="hfEnd" /></MultiHandleSliderTargets></asp:MultiHandleSliderExtender><asp:HiddenField ID="hfStart" runat="server" /><asp:HiddenField ID="hfEnd" runat="server" /><asp:TextBox ID="txtSlider" runat="server"></asp:TextBox><asp:LinkButton ID="lnkSliderChanged" OnClick="SliderChanged" runat="server" /><script type="text/javascript">
                function OnClientDragEnd(sender, args) {
                    document.getElementById("<%=lnkSliderChanged.ClientID %>").click();
                }</script><br /><hr /><asp:DataList ID="dlProducts" runat="server" RepeatLayout="Table" RepeatColumns="3"
                CellPadding="2" CellSpacing="20"><ItemTemplate><table class="item" cellpadding="0" cellspacing="0" border="0"><tr><td align="center" class="header"><span class="name"><%# Eval("Name") %></span></td></tr><tr><td align="center" class="body"><asp:Image ImageUrl='<%# Eval("ProductId", "~/images/{0}.png")%>' runat="server"
                                    CssClass="image" /></td></tr><tr><td class="footer" align="center"><span class="button"><%# Eval("Price") %></span></td></tr></table></ItemTemplate></asp:DataList></ContentTemplate></asp:UpdatePanel></asp:Content>

c # code 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
public partial class Default4 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
this.BindDataList();
}

}
protected void SliderChanged(object sender, EventArgs e)
{
System.Threading.Thread.Sleep(2000);
this.BindDataList();
}

private void BindDataList()
{
string constr = ConfigurationManager.ConnectionStrings["ErpConnection1"].ConnectionString;
int start = !string.IsNullOrEmpty(Request.Form[hfStart.UniqueID]) ? int.Parse(Request.Form[hfStart.UniqueID]) : 0;
int end = !string.IsNullOrEmpty(Request.Form[hfEnd.UniqueID]) ? int.Parse(Request.Form[hfEnd.UniqueID]) : 0;
using (SqlConnection con = new SqlConnection(constr))
{
string query = "SELECT * FROM Products WHERE (Price BETWEEN @Start AND @End) OR (@Start = 0 AND @End = 0);";
query += "SELECT MIN(Price) [Min], MAX(Price) [Max] FROM Products";
using (SqlCommand cmd = new SqlCommand(query))
{
cmd.Connection = con;
cmd.Parameters.AddWithValue("@Start", start);
cmd.Parameters.AddWithValue("@End", end);
using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
{
DataSet ds = new DataSet();
sda.Fill(ds);
dlProducts.DataSource = ds.Tables[0];
dlProducts.DataBind();
if (!this.IsPostBack)
{
hfStart.Value = ds.Tables[1].Rows[0]["Min"].ToString();
hfEnd.Value = ds.Tables[1].Rows[0]["Max"].ToString();
}
}
}
}
}
}