<script type="text/javascript">

    function get_mobile_code() {

        $.get('Post.aspx', { mobile: jQuery.trim($('#mobile').val()) }, function (msg) {

            alert(jQuery.trim(unescape(msg)));

            if (msg == '提交成功') {

                RemainTime();

            }

        });

    };

    var iTime = 59;

    var Account;

    function RemainTime() {

        document.getElementById('zphone').disabled = true;

        var iSecond, sSecond = "", sTime = "";

        if (iTime >= 0) {

            iSecond = parseInt(iTime % 60);

            iMinute = parseInt(iTime / 60)

            if (iSecond >= 0) {

                if (iMinute > 0) {

                    sSecond = iMinute + "分" + iSecond + "秒";

                } else {

                    sSecond = iSecond + "秒";

                }

            }

            sTime = sSecond;

            if (iTime == 0) {

                clearTimeout(Account);

                sTime = '获取手机验证码';

                iTime = 59;

                document.getElementById('zphone').disabled = false;

            } else {

                Account = setTimeout("RemainTime()", 1000);

                iTime = iTime - 1;

            }

        } else {

            sTime = '没有倒计时';

        }

        document.getElementById('zphone').value = sTime;

    }

</script>

<form action="" method="post" name="formUser" onSubmit="return register();">

    <table width="100%" border="0" align="left" cellpadding="5" cellspacing="3">

        <tr>

        <td align="right">手机<td>

        <input id="mobile" name="extend_field5" type="text" size="25" class="inputBg" /><span style="color:#FF0000"> *</span>

        <input id="zphone" type="button" value=" 发送手机验证码 " onClick="get_mobile_code();"></td>

        </tr>

        <tr>

            <td align="right">验证码</td>

            <td><input type="text" size="8" name="captcha" class="inputBg" /></td>

        </tr>

    </table>

</form>

 public static string PostUrl = ConfigurationManager.AppSettings["WebReference.Service.PostUrl"];

        protected void Page_Load(object sender, EventArgs e)

        {

            string account = "C23795760";//用户名是登录用户中心->验证码、通知短信->帐户及签名设置->APIID

            string password = "b79bc3ff3985ea849964fb7a5fdf78ea"; //密码是请登录用户中心->验证码、通知短信->帐户及签名设置->APIKEY

            string mobile = Request.QueryString["mobile"];

            Random rad = new Random();

            int mobile_code = rad.Next(1000, 10000);

            string content = "我就是来测试的别害怕zmd：" + mobile_code + " 。请不要把验证码泄露给其他人。";

            //Session["mobile"] = mobile;

            //Session["mobile_code"] = mobile_code;

            string postStrTpl = "account={0}&password={1}&mobile={2}&content={3}";

            UTF8Encoding encoding = new UTF8Encoding();

            byte[] postData = encoding.GetBytes(string.Format(postStrTpl, account, password, mobile, content));

            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(PostUrl);

            myRequest.Method = "POST";

            myRequest.ContentType = "application/x-www-form-urlencoded";

            myRequest.ContentLength = postData.Length;

            Stream newStream = myRequest.GetRequestStream();

            // Send the data.

            newStream.Write(postData, 0, postData.Length);

            newStream.Flush();

            newStream.Close();

            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();

            if (myResponse.StatusCode == HttpStatusCode.OK)

            {

                StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);

                //Response.Write(reader.ReadToEnd());

                string res = reader.ReadToEnd();

                int len1 = res.IndexOf("</code>");

                int len2 = res.IndexOf("<code>");

                string code = res.Substring((len2 + 6), (len1 - len2 - 6));

                //Response.Write(code);

                int len3 = res.IndexOf("</msg>");

                int len4 = res.IndexOf("<msg>");

                string msg = res.Substring((len4 + 5), (len3 - len4 - 5));

                Response.Write(msg);

                Response.End();

            }

            else

            {

                //访问失败

            }

        }

 <appSettings>

    <add key="WebReference.Service.PostUrl" value="http://106.ihuyi.cn/webservice/sms.php?method=Submit"/>

    <add key="WebReference.sms" value="http://106.ihuyi.cn/webservice/sms.php?smsService"/>

  </appSettings>