Bind a Dropdown List via jQuery and JSON (using JavaScriptSerializer)

<div>     
        <asp:Button ID="btnGetMsg" runat="server" Text="Click Me" OnClientClick="DisplayMessageCall();return false;" /><br />
        <asp:Label ID="lblOutput" runat="server" Text=""></asp:Label>
        <table id="container">
        <tr>
            <th>MaterialName
            </th>
            <th>QuantityType
            </th>
        </tr>
    </table><br /><br />
    
    <asp:DropDownList ID="ddlNo" runat="server"></asp:DropDownList>
    </div>

<script type="text/javascript">
        function DisplayMessageCall() {
            $.ajax({
                url: "Handler.ashx",
                data: "",
                type: "GET",
                datatype: 'json',
                success: function (data) {
                    $("#container tr+tr").remove();
                    var table = $("#container");
                    var list = $("#ddlNo");
                    var listItems = "";
                    $(data).each(function (i) {
                        listItems += "<option value='" + data[i].MaterialName + "'>" + data[i].QuantityType + "</option>";
                    }

                    );
                    $("#ddlNo").html(listItems);
                },
                error: OnErrorCall
            });
        }

        function OnSuccessCall(response) {
            $('#<%=lblOutput.ClientID%>').html(response);


        }

        function OnErrorCall(response) {
            alert(response.status + " " + response.statusText);
        }
    </script>

using System.Collections.Generic;

public class Handler : IHttpHandler {
    
    public void ProcessRequest (HttpContext context)    
    {
        context.Response.ContentType = "application/json";
        string period = context.Request.QueryString["Period"];
       List<MaterialEntity> objList = new List<MaterialEntity>();
        for (int i = 0; i < 10; i++)
        {
            objList.Add(new MaterialEntity()
            {
                MaterialName =  period + " " + i.ToString(),
                QuantityType =  period + " " + i.ToString()
            });
        }
        System.Web.Script.Serialization.JavaScriptSerializer oSerializer =
         new System.Web.Script.Serialization.JavaScriptSerializer();
        string sJSON = oSerializer.Serialize(objList);  
        context.Response.Write(sJSON);
    }
 
 
    public bool IsReusable {
        get {
            return false;
        }
    }

}
public class MaterialEntity
{
    public string MaterialName { get; set; }
    public string QuantityType { get; set; }
}