怎么在js的post中加入accept=json

我想用js发送post消息给服务器，并且要求返回json格式的数据，我查了一下jquery的文档，但是还是没办法把accept=json加入到header中。代码如下

function getCode(param, config, notice){
        var url = config.apiBase
                + "/resource/";
        var data = {
                "name": param.name,
                "user_agent": param.ua,
                "mobile": $("#phone").val()
        };

        $.post(url, data, )
                .done(function(data){
                        console.log(data);
                        if(data.ret){
                                notice.showMsg({
                                        msg: "短信验证码已经发送。",
                                        type: "info",
                                        deley: 0,
                                        duration: 0,
                                        close: true
                                });
                                countDown();
                        }else{
                                notice.showMsg({
                                        msg: "短信验证码发送失败。",
                                        type: "error",
                                        deley: 0,
                                        duration: 0,
                                        close: true
                                });
                        }
                })

---

$.ajax({ url: url,
    type: "POST",
    data: data,
    beforeSend: function(req) {
        req.setRequestHeader("Accept", "application/json");
    },
    success: function(json) {
        // do something...
    },
    error: function(xhr) {
        // do something...
    }});

---

$.post(url,$.noop,'json')

$.post(url,postDataObject,$.noop,'json')

$.post(url,postDataString,$.noop,'json')

---

$.ajax({url: ajaxUrl,
        type: 'POST',
        dataType: 'json',
        contentType: 'application/json; charset=UTF-8',
        data: JSON.encode(params),
     }).then(function(data) {
                return data;
            });

http://api.jquery.com/jQuery.ajax/

看文档，

contentType (default: 'application/x-www-form-urlencoded; charset=UTF-8')
Type: String
When sending data to the server, use this content type. Default is "application/x-www-form-urlencoded; charset=UTF-8", which is fine for most cases. If you explicitly pass in a content-type to $.ajax(), then it is always sent to the server (even if no data is sent). The W3C XMLHttpRequest specification dictates that the charset is always UTF-8; specifying another charset will not force the browser to change the encoding. Note: For cross-domain requests, setting the content type to anything other than application/x-www-form-urlencoded, multipart/form-data, or text/plain will trigger the browser to send a preflight OPTIONS request to the server.

这一段的介绍，可以在配置参数中，修改传输的格式，默认是 'application/x-www-form-urlencoded; charset=UTF-8'。

---

$.post() 不支持加入 headers 信息，改用 $.ajax()。demo 如下：

function getCode(param, config, notice) {
    var url = config.apiBase
            + "/resource/";
    var data = {
        "name": param.name,
        "user_agent": param.ua,
        "mobile": $("#phone").val()
    };

    $.ajax({
        url: url,
        type: 'post',
        data: data,
        headers: {
            "X-Requested-Accept": 'json'
        },
        dataType: 'json',
        success: function (data) {
            console.log(data);
            if (data.ret) {
                notice.showMsg({
                    msg: "短信验证码已经发送。",
                    type: "info",
                    deley: 0,
                    duration: 0,
                    close: true
                });
                countDown();
            } else {
                notice.showMsg({
                    msg: "短信验证码发送失败。",
                    type: "error",
                    deley: 0,
                    duration: 0,
                    close: true
                });
            }
        }
    });
}

---

    $.ajax({
        type: 'POST',
        url: "http://kycool-girl.com/head.php",
        headers: {
            "access":"json",
        }
    }).done(function(data) { 
        console.log(data);
    });

请求的头

Remote Address:127.0.0.1:80
Request URL:http://kycool-girl.com/head.php
Request Method:POST
Status Code:200 OK
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:zh-CN,zh;q=0.8,en;q=0.6
access:json
Cache-Control:no-cache
Connection:keep-alive
Content-Length:0
Host:kycool-girl.com
Origin:http://127.0.0.1:8000
Pragma:no-cache

后端简单设置 PHP 文件

    header('Access-Control-Allow-Origin: *');
    header('Access-Control-Allow-Headers: Content-Type, Content-Range, Content-Disposition, Content-Description, access');

    $data = array("name"=>"allen", "age"=>27);

    echo json_encode($data);