<div class="form">
                        <dl>
                            <dt>您的稱呼<small>(必填)</small></dt>
                            <dd><input id="name" type="text" name="name" class="formText" require></dd>
                        </dl>
                        <dl>
                            <dt>您的郵箱<small>(必填)</small></dt>
                            <dd><input id="
 
email" type="text" name="email" class="formText" require></dd>
                        </dl>
                        <dl>
                            <dt>聯系電話</dt>
                            <dd><input id="phone" type="text" name="phone" class="formText"></dd>
                        </dl>
                        <dl>
                            <dt>您的想法/意見<small>(必填)</small></dt>
                            <dd><textarea id="
 
message" name="message" class="formText"></textarea></dd>
                        </dl>
                        <div class="formBtn" onclick="btnSend()">發送留言</div>
                        <script>
                            //提交數據
                            function btnSend() {
                                $(
 
"#txtMsg").text("");
                                var name = $("#name").val();//您的稱呼
                                var email = $("#email").val();//您的郵箱
                                var phone = $("#phone").val();//聯系電話
                                var message = $("#message").val();//您的想法

                                if (name.length == 0) {
                                    alert("稱呼不能為空!");
                                    return;
                                }
                                if (email.length == 0) {
                                    alert("郵箱不能為空!");
                                    return;
                                }

                                var myreg = /^([a-zA-Z0-9]+[_|\_|\.]?)*[a-zA-Z0-9]+@([a-zA-Z0-9]+[_|\_|\.]?)*[a-zA-Z0-9]+\.[a-zA-Z]{2,3}$/;
                                if (!myreg.test(email)) {
                                    alert(‘請輸入有效的E_mail!‘);
                                    return;
                                }

                                if (message.length < 20) {
                                    alert("意見不能不能少於20個字符!");
                                    return;
                                }
                                $(".formBtn").val("正在發送，請稍等！");

                                var postData = "name=" + name + "&email=" + email + "&phone=" + phone + "&message=" + message;

                                //向後臺發送處理數據
                                $.ajax({
                                    type: "POST", //用POST方式傳輸
                                    dataType: "text", //數據格式:JSON
                                    url: ‘/Email.ashx‘, //目標地址
                                    data: postData,
                                    error: function (XMLHttpRequest, textStatus, errorThrown) {
                                        alert("發送失敗，請聯系在線客服！");
                                    },
                                    success: function (msg) {
                                        $(".formBtn").val("發送留言");
                                        alert(msg);
                                    }
                                });
                            }

                        </script>
                    </div>

Email.ashx

<%@ WebHandler Language="C#" Class="Email" %>

using System;
using System.Web;
using Ky.Common;


public class Email : IHttpHandler
{

    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "text/plain";

        string name = KYRequest.GetFormString("name");//您的稱呼
        string email = KYRequest.GetFormString("email");//您的郵箱
        string phone = KYRequest.GetFormString("phone");//聯系電話
        string message = KYRequest.GetFormString("message");//您的想法

        if (string.IsNullOrEmpty(name))
        {
            context.Response.Write("您的稱呼為空");
            return;
        }
        if (string.IsNullOrEmpty(email))
        {
            context.Response.Write("您的郵箱為空");
            return;
        }
        if (string.IsNullOrEmpty(message))
        {
            context.Response.Write("想法/意見為空");
            return;
        }
        string body = "時間：" + DateTime.Now + "<br>IP：" + KYRequest.GetIP() + "<br>稱呼：" + name + "<br>郵箱：" + email + "<br>電話：" + phone + "<br>想法/意見：" + message;

        try
        {
            string wwwEmail = System.Configuration.ConfigurationManager.AppSettings["wwwEmail"].ToString();
            SendMail.Send(wwwEmail, "【郵件助手】您的網站收到留言" + DateTime.Now, body);
            context.Response.Write("發送成功，感謝您的支持。");
        }
        catch
        {
            context.Response.Write("Web.config未設置接收郵箱，發送失敗");
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}

jquery ajax 發送郵件例子