public void ProcessRequest(HttpContext context)

        {

            //解决跨域问题

            context.Response.ClearHeaders();

            context.Response.AppendHeader("Access-Control-Allow-Origin", "*");

            string requestHeaders = context.Request.Headers["Access-Control-Request-Headers"];

            context.Response.AppendHeader("Access-Control-Allow-Headers",

            string.IsNullOrEmpty(requestHeaders) ? "*" : requestHeaders);

            context.Response.AppendHeader("Access-Control-Allow-Methods", "POST, OPTIONS");

            context.Response.AppendHeader("Content-type", "application/json");

            string action = context.Request.QueryString["action"];

            switch (action)

            {

                case "get_total_pages":

                    getTotalPages();

                    break;

                default:

                    output();

                    break;

            }

        }

    <httpProtocol>

      <customHeaders>

        <add name="Access-Control-Allow-Methods" value="POST,GET"/>

        <add name="Access-Control-Allow-Headers" value="x-requested-with"/>

        <add name="Access-Control-Allow-Origin" value="http://localhost:22779" />

      </customHeaders>

    </httpProtocol>