ajax设置头信息，读取头信息

function GetDateForServiceCustomer(userId) {
    $.ajax({
        url: 'http://*******/api/orders',
        data: {
            currUserId: userId,
            type: 1
        },
        beforeSend: function(request) {
            request.setRequestHeader("Authorization", token);
        },

        /*headers: {
            "Access-Control-Allow-Origin":"http://example.edu",
            "Access-Control-Allow-Headers":"X-Requested-With"
        }*/

        dataType: 'JSON',
        async: false,//请求是否异步，默认为异步
        type: 'GET',
        success: function (list) {
        },
        error: function () {
        }
    });
}

 　　　　　　 var xmlhttp = new XMLHttpRequest();
            var obj = {
                name: 'zhansgan',
                age: 18
            };
            xmlhttp.open("POST", "http://192.168.1.200:8080/php/test.php", true);
            xmlhttp.setRequestHeader("token","header-token-value"); // 可以定义请求头带给后端
            xmlhttp.setRequestHeader("dingyi","header-dingyi-value");
            xmlhttp.send(JSON.stringify(obj));  // 要发送的参数，要转化为json字符串发送给后端，后端就会接受到json对象
            // readyState == 4 为请求完成，status == 200为请求陈宫返回的状态
            xmlhttp.onreadystatechange = function(){
                if(xmlhttp.readyState == 4 && xmlhttp.status == 200){
                    console.log(xmlhttp.responseText);
                }
            }

$.get(url, function(data, statusTest, xhr){
    console.log(xhr);
    console.log(xhr.getAllResponseHeaders());//获取所有的响应头消息
    //console.log(xhr.getResponseHeader('server'));//获取服务器信息   
});

function createXmlHttp() {
    var xmlhttp = null;
    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp = new XMLHttpRequest();
    }else{// code for IE6, IE5
      xmlhttp = new ActiveXO相应bject("Microsoft.XMLHTTP");
    }
    return xmlhttp;  
}
var xmlhttp = createXmlHttp();
xmlhttp.open("GET", url, true);
xmlhttp.send();
xmlhttp.onreadystatechange=function(){//设置状态发生变化时候监听函数
    if(xmlhttp.readyState ==4 && 200 == xmlhttp.status){
        console.log(xmlhttp.getAllResponseHeaders());//获取所有的响应头消息
        //console.log(xmlhttp.getResponseHeader('server')); //获取服务器信息        
    }
}