ajax: function( origSettings ) {
  var s = jQuery.extend(true, {}, jQuery.ajaxSettings, origSettings);
  
  // ............... 去掉一些无关的代码

  // convert data if not already a string
  if (s.data && s.processData && typeof s.data !== "string") {
    // 注意下面这个调用
    s.data = jQuery.param( s.data, s.traditional );
  }

// Serialize an array of form elements or a set of
// key/values into a query string
param: function( a, traditional ) {
  var s = [];
  // ............... 去掉一些无关的代码
  
  // If an array was passed in, assume that it is an array of form elements.
  if ( jQuery.isArray(a) || a.jquery ) {
    // Serialize the form elements
    jQuery.each( a, function() {
      add( this.name, this.value );
    });
    
  } else {
    // ............... 去掉一些非重点代码
  }

  // Return the resulting serialization
  return s.join("&").replace(r20, "+");

  function add( key, value ) {
    // If value is a function, invoke it and return its value
    value = jQuery.isFunction(value) ? value() : value;
    s[ s.length ] = encodeURIComponent(key) + "=" + encodeURIComponent(value);
  }
}

<globalization requestEncoding="gb2312" responseEncoding="gb2312" />

$.ajax({
  // 注意下面这行代码，它为请求添加一个自定义请求头
  beforeSend: function(xhr) {  xhr.setRequestHeader("x-charset", "utf-8"); },
  
  url: "/TestParam.ashx", type: "GET", cache: false,
  data: { id: 2,
    name: "fish li + is me.",
    tel: "~!@#$%^&*()_+-=<>?|",          
    "x?x!x&x": "aa=2&bb=3&cc=汉字。", // 特殊的键名，值内容也特殊。
    encoding: "见鬼去吧。?& :)",
    中文键名: "大明王朝1368"
  },
  success: function(responseText) {
    $("#divResult").html(responseText);
  }
});

beforeSend: function(xhr) {  xhr.setRequestHeader("x-charset", "utf-8"); },

public class ContentEncodingModule : IHttpModule
{
  public void Init(HttpApplication app)
  {
    app.BeginRequest += new EventHandler(app_BeginRequest);
  }

  void app_BeginRequest(object sender, EventArgs e)
  {
    HttpApplication app = (HttpApplication)sender;
    HttpWorkerRequest request = (((IServiceProvider)app.Context)
              .GetService(typeof(HttpWorkerRequest)) as HttpWorkerRequest);

    // 注意：我并没有使用 app.Request.Headers["x-charset"]
    // 因为：绝大部分程序不访问它，它将一直保持是 null，
    // 如果我此时该问这个集合，会导致填充它。
    // 我认为填充Headers集合比我下面的调用的成本要高很多，
    // 所以，直接通过HttpWorkerRequest读取请求头对性能的损耗会最小。
    
    string charset = request.GetUnknownRequestHeader("x-charset");
    if( string.Compare(charset, "utf-8", StringComparison.OrdinalIgnoreCase) == 0 )

      // ASP.NET在填充QueryString,Form时，会访问Request.ContentEncoding做为解码时使用的字符编码
      app.Request.ContentEncoding = System.Text.Encoding.UTF8;
  }

$(function() {
  var cookie = $.cookie("TestJsRead");
  $("#cookieValue").text(cookie);
});

cookie = new HttpCookie("TestJsRead", HttpUtility.UrlEncode("大明王朝1368"));
Response.Cookies.Add(cookie);

public void ProcessRequest(HttpContext context)
{
  byte[] fileContent = GetFileContent();
  context.Response.ContentType = "application/octet-stream";

  string downloadName = "ClownFish性能测试结果.xlsx";
  string headerValue = string.Format("attachment; filename="{0}"", downloadName);
  context.Response.AddHeader("Content-Disposition", headerValue);

  context.Response.OutputStream.Write(fileContent, 0, fileContent.Length);
}