jQuery.ajax 调用 服务（.aspx，.asmx）

方法1：Post（json）+IIS下；//aspx，适用本机

        $.ajax({
            url: "TpgConnect_Rain/postgreService.aspx/getRainInfo",
            type: "POST", //使用Post方式请求
            contentType: "application/json;charset=utf-8",
            data: "{}", //这里是要传递的参数，格式为 data: "{value1:'心想事成',i:10}"
            dataType: "json",
            success: function (result) {
                datas_rain = JSON.parse(result.d);
                alert(datas_rain);
            },
            error: function (x, e) {
                alert("error:" + x.responseText);
            }
        });

方法2：Get（jsonp）；//aspx，可解决跨域　　

        $.ajax({
            url: "http://10.19.1.54/TpgConnect_Rain/postgreService.aspx/getRainInfo?method=rain",
            type: "GET", //使用GET方式请求
            dataType: "JSONP",
            jsonp: "callback",
            data: "{}",
            success: function (result) {
                datas_rain = JSON.parse(result);
                alert(datas_rain);
            },
            error: function (x, e) {
                alert("error:" + x.responseText);
            }
        });

方法3：XMLHttpRequest；//aspx，传统方式

        var xmlhttp = new XMLHttpRequest();
        window.onload = function () {
            var url = "http://localhost/TpgConnect/postgreService.aspx?method=rain";
            xmlhttp.open("post", url, true);
            xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            xmlhttp.onreadystatechange = updatePage;
            xmlhttp.send(null);
        }

        function updatePage() {
            if (xmlhttp.readyState == 4) {
                if (xmlhttp.status == 200 || xmlhttp.status == 0) {
                    alert(eval(xmlhttp.responseText)[0].stationno);
                }
                else
                    alert(xmlhttp.status);
            }
        }

方法4：Post（json）+IIS下；//asmx，适用本机　

        $.ajax({
            type: "POST",
            contentType: "application/json;charset=utf-8",
            url: "WebService.asmx/GetWish",
            data: "{value1:'心想事成',value2:'万事如意',value3:'牛牛牛',value4:2009}",
            dataType: "json",
            success: function (json) {
                alert("success" + json.d);
            },
            error: function (x, e) {
                alert("error" + x.responseText);
            }
        });

说明：

1）尽量使用post，无参时：data: ""，将返回xml格式；data: "{}"，将返回json格式

2）get参数有中文时需要编码，而post不需要

附:

        /* ASP.NET服务源码（aspx）*/
        protected void Page_Load(object sender, EventArgs e)
        {
            Response.AddHeader("Access-Control-Allow-Origin", "*");
            string result = "";
            var val1 = Request.QueryString["val1"];
            var val2 = Request.QueryString["val2"];
            var val3 = Request.QueryString["val3"];
            var callback = Request.QueryString["method"];
            if (callback == "rain")
                result = getRainInfo();
            else if (callback == "pond")
                result = getPondInfo();
            else if (callback == "snow")
                result = getSnowInfo();
            Response.Write(result);
            Response.End();
        }

        /* WebService服务源码（asmx） */
        [System.Web.Script.Services.ScriptService]
        public class WebService : System.Web.Services.WebService
        {
            public WebService()
            {
            }
            [WebMethod]
            public string GetWish(string value1, string value2, string value3, int value4)
            {
                return string.Format("祝您在{3}年里 {0}、{1}、{2}", value1, value2, value3, value4);
            }
        }