Set Class and Style attribute using WebService and Ajax in ASP.Net

Hi nauna,

Refer below example.

HTML

<div id="dvproducthomebox">
    <asp:Label ID="lblproducthometitle" runat="server" />
</div>
<style type="text/css">
    body { font-family: Arial; font-size: 10pt; }
    .countcss { border: 2px solid green; text-align: center; }
</style>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $.ajax({
            type: "POST",
            url: "WebService.asmx/get_product_setting",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            data: {},
            success: function (data) {
                $('#lblproducthometitle').html(data.d.Title);
                $('#dvproducthomebox').attr("class", data.d.productcountcss);
                $('#dvproducthomebox').attr("style", data.d.backgrouncolorcss);
            },
            error: function (response) {
                alert(response.responseText);
            }
        });
    });
</script>

WebService

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

/// <summary>
/// Summary description for WebService
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
[System.Web.Script.Services.ScriptService]
public class WebService : System.Web.Services.WebService
{
    [WebMethod]
    public Setting get_product_setting()
    {
        return new Setting
        {
            Title = "Wel come to ASPSnippets.",
            productcountcss = "countcss",
            backgrouncolorcss = "background-color: red;"
        };
    }

    public class Setting
    {
        public string Title { get; set; }
        public string productcountcss { get; set; }
        public string backgrouncolorcss { get; set; }
    }
}

Screenshot