另一种从JavaScript发送电子邮件的方法是使用directtomx.com，如下所示;

 Email = {
 Send : function (to,from,subject,body,apikey)
    {
        if (apikey == undefined)
        {
            apikey = Email.apikey;
        }
        var nocache= Math.floor((Math.random() * 1000000) + 1);
        var strUrl = "http://directtomx.azurewebsites.net/mx.asmx/Send?";
        strUrl += "apikey=" + apikey;
        strUrl += "&from=" + from;
        strUrl += "&to=" + to;
        strUrl += "&subject=" + encodeURIComponent(subject);
        strUrl += "&body=" + encodeURIComponent(body);
        strUrl += "&cachebuster=" + nocache;
        Email.addScript(strUrl);
    },
    apikey : "",
    addScript : function(src){
            var s = document.createElement( 'link' );
            s.setAttribute( 'rel', 'stylesheet' );
            s.setAttribute( 'type', 'text/xml' );
            s.setAttribute( 'href', src);
            document.body.appendChild( s );
    }
};

然后从页面中调用它，如下所示;

 window.onload = function(){
    Email.apikey = "-- Your api key ---";
    Email.Send("to@domain.com","from@domain.com","Sent","Worked!");
 }

因为这些都是很棒的信息，有一个叫做Mandrill的小api可以从javascript发送邮件，它工作得很完美。你可以试试。这里有一个开始的小教程。

我找不到一个能真正满足最初问题的答案。

Mandrill是不可取的，因为它是新的定价政策，加上它需要一个后端服务，如果你想保持你的凭证安全。 最好隐藏你的电子邮件，这样你就不会出现在任何列表中(mailto解决方案暴露了这个问题，对大多数用户来说不方便)。 仅仅为了发送一封电子邮件而设置sendMail或需要一个后端是很麻烦的。

我提供了一个简单的免费服务，允许您发出标准的HTTP POST请求来发送电子邮件。它叫做PostMail，你可以使用JavaScript或jQuery简单地发布一个表单。当你注册时，它为你提供代码，你可以复制和粘贴到你的网站。下面是一些例子:

JavaScript:

<form id="javascript_form">
    <input type="text" name="subject" placeholder="Subject" />
    <textarea name="text" placeholder="Message"></textarea>
    <input type="submit" id="js_send" value="Send" />
</form>

<script>

    //update this with your js_form selector
    var form_id_js = "javascript_form";

    var data_js = {
        "access_token": "{your access token}" // sent after you sign up
    };

    function js_onSuccess() {
        // remove this to avoid redirect
        window.location = window.location.pathname + "?message=Email+Successfully+Sent%21&isError=0";
    }

    function js_onError(error) {
        // remove this to avoid redirect
        window.location = window.location.pathname + "?message=Email+could+not+be+sent.&isError=1";
    }

    var sendButton = document.getElementById("js_send");

    function js_send() {
        sendButton.value='Sending…';
        sendButton.disabled=true;
        var request = new XMLHttpRequest();
        request.onreadystatechange = function() {
            if (request.readyState == 4 && request.status == 200) {
                js_onSuccess();
            } else
            if(request.readyState == 4) {
                js_onError(request.response);
            }
        };

        var subject = document.querySelector("#" + form_id_js + " [name='subject']").value;
        var message = document.querySelector("#" + form_id_js + " [name='text']").value;
        data_js['subject'] = subject;
        data_js['text'] = message;
        var params = toParams(data_js);

        request.open("POST", "https://postmail.invotes.com/send", true);
        request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

        request.send(params);

        return false;
    }

    sendButton.onclick = js_send;

    function toParams(data_js) {
        var form_data = [];
        for ( var key in data_js ) {
            form_data.push(encodeURIComponent(key) + "=" + encodeURIComponent(data_js[key]));
        }

        return form_data.join("&");
    }

    var js_form = document.getElementById(form_id_js);
    js_form.addEventListener("submit", function (e) {
        e.preventDefault();
    });
</script>

jQuery:

<form id="jquery_form">
    <input type="text" name="subject" placeholder="Subject" />
    <textarea name="text" placeholder="Message" ></textarea>
    <input type="submit" name="send" value="Send" />
</form>

<script>

    //update this with your $form selector
    var form_id = "jquery_form";

    var data = {
        "access_token": "{your access token}" // sent after you sign up
    };

    function onSuccess() {
        // remove this to avoid redirect
        window.location = window.location.pathname + "?message=Email+Successfully+Sent%21&isError=0";
    }

    function onError(error) {
        // remove this to avoid redirect
        window.location = window.location.pathname + "?message=Email+could+not+be+sent.&isError=1";
    }

    var sendButton = $("#" + form_id + " [name='send']");

    function send() {
        sendButton.val('Sending…');
        sendButton.prop('disabled',true);

        var subject = $("#" + form_id + " [name='subject']").val();
        var message = $("#" + form_id + " [name='text']").val();
        data['subject'] = subject;
        data['text'] = message;

        $.post('https://postmail.invotes.com/send',
            data,
            onSuccess
        ).fail(onError);

        return false;
    }

    sendButton.on('click', send);

    var $form = $("#" + form_id);
    $form.submit(function( event ) {
        event.preventDefault();
    });
</script>

再次坦白地说，我创建这个服务是因为我找不到合适的答案。

你的问题没有一个直接的答案，因为我们不能只使用javascript发送电子邮件，但有一些方法可以使用javascript为我们发送电子邮件:

1)使用API并通过javascript调用API为我们发送电子邮件，例如https://www.emailjs.com说你可以在一些设置后使用下面的代码来调用他们的API:

var service_id = 'my_mandrill';
var template_id = 'feedback';
var template_params = {
name: 'John',
reply_email: 'john@doe.com',
message: 'This is awesome!'
};

emailjs.send(service_id,template_id,template_params);

2)创建一个后端代码来为你发送电子邮件，你可以使用任何后端框架来为你做这件事。

3)使用像这样的东西:

window.open('mailto:me@http://stackoverflow.com/');

这将打开你的电子邮件应用程序，这可能会进入阻止弹出在你的浏览器。

一般来说，发送电子邮件是一个服务器任务，所以应该在后端语言中完成，但我们可以使用javascript来收集所需的数据，并将其发送到服务器或api，我们也可以使用第三方应用程序，并通过浏览器使用javascript打开它们。

Javascript是客户端，你不能用Javascript发邮件。浏览器可能只识别mailto:，并启动默认的邮件客户端。

使用JavaScript或jQuery发送邮件

var ConvertedFileStream;
var g_recipient;
var g_subject;
var g_body;
var g_attachmentname;


function SendMailItem(p_recipient, p_subject, p_body, p_file, p_attachmentname, progressSymbol) {

    // Email address of the recipient 
    g_recipient = p_recipient;

   // Subject line of an email
    g_subject = p_subject;

   // Body description of an email
    g_body = p_body;

    // attachments of an email
    g_attachmentname = p_attachmentname;

    SendC360Email(g_recipient, g_subject, g_body, g_attachmentname);

}

function SendC360Email(g_recipient, g_subject, g_body, g_attachmentname) {
    var flag = confirm('Would you like continue with email');
    if (flag == true) {

        try {
            //p_file = g_attachmentname;
            //var FileExtension = p_file.substring(p_file.lastIndexOf(".") + 1);
           // FileExtension = FileExtension.toUpperCase();
            //alert(FileExtension);
            SendMailHere = true;

            //if (FileExtension != "PDF") {

            //    if (confirm('Convert to PDF?')) {
            //        SendMailHere = false;                    
            //    }

            //}
            if (SendMailHere) {
                var objO = new ActiveXObject('Outlook.Application');

                var objNS = objO.GetNameSpace('MAPI');

                var mItm = objO.CreateItem(0);

                if (g_recipient.length > 0) {
                    mItm.To = g_recipient;
                }

                mItm.Subject = g_subject;

                // if there is only one attachment                 
                // p_file = g_attachmentname;
                // mAts.add(p_file, 1, g_body.length + 1, g_attachmentname);

                // If there are multiple attachment files
                //Split the  files names
                var arrFileName = g_attachmentname.split(";");
                 // alert(g_attachmentname);
                //alert(arrFileName.length);
                var mAts = mItm.Attachments;

                for (var i = 0; i < arrFileName.length; i++)
                {
                    //alert(arrFileName[i]);
                    p_file = arrFileName[i];
                    if (p_file.length > 0)
                    {                     
                        //mAts.add(p_file, 1, g_body.length + 1, g_attachmentname);
                        mAts.add(p_file, i, g_body.length + 1, p_file);

                    }
                }

                mItm.Display();

                mItm.Body = g_body;

                mItm.GetInspector.WindowState = 2;

            }
            //hideProgressDiv();

        } catch (e) {
            //debugger;
            //hideProgressDiv();
            alert('Unable to send email.  Please check the following: \n' +
                    '1. Microsoft Outlook is installed.\n' +
                    '2. In IE the SharePoint Site is trusted.\n' +
                    '3. In IE the setting for Initialize and Script ActiveX controls not marked as safe is Enabled in the Trusted zone.');
        }
    }
  }