How to Export the CSV data passed to web method get exported into Excel

I have comma separated data on client side [Since my columns and rows are dynamic along with dynamic control inside it which are not accessible in backend due to viewstate issue of dynamic controls],

So I am passing CSV string to Web Method as and want to get Excel file out of it.

How to accomplish the same ?

I tried following code but it is not exporting the file.

[System.Web.Services.WebMethod]
        public static void CSV2Excel(string csv)
        {
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=FileName.csv");
            HttpContext.Current.Response.Charset = "";
            HttpContext.Current.Response.ContentType = "application/octet-stream";
            HttpContext.Current.Response.Write(csv);
            HttpContext.Current.Response.End();
        }