//Student person = new Student() { Name = "张三",Code="001" };
   //JavaScriptSerializer json = new JavaScriptSerializer();
   //string str = json.Serialize(person);
   context.Response.Write(str);

 $(document).ready(
   function () {
    $.post("Test.ashx", function (data, status) {
     if (status == "success") {
      var person = $.parseJSON(data);
      alert(person.Name);
    });
   }
  );

public string SerializeDataTable(DataTable dt) 
  {
   StringBuilder sb = new StringBuilder();
   sb.Append("[");
   for (int i = 0; i < dt.Rows.Count; i++)
   {
    sb.Append("{");
    for (int j = 0; j < dt.Columns.Count; j++)
    {
     sb.Append("\"" + dt.Columns[j].ColumnName + "\":\"" + dt.Rows[i][j].ToString() + "\"");
     if (j < dt.Columns.Count - 1)
     {
      sb.Append(",");
     }
    }
    sb.Append("}");
    if (i < dt.Rows.Count - 1)
    {
     sb.Append(",");
    }
   }
   sb.Append("]");
   return sb.ToString();
  }

$(document).ready(
   function () {
    $.post("Test.ashx", function (data, status) {
     if (status == "success") {
      var person = $.parseJSON(data);
      $.each(person, function (k, v) {
       alert(v.Name);
       alert(v.Code);
      });
     }
    });
   }
  );