javascript 實現Ajax 資源請求

XMLHttpRequest

---

var xmlhttp = new XMLHttpRequest();
        xmlhttp.open("POST", "http://127.0.0.1:6767/api/v1/login", true);
        xmlhttp.send();
        xmlhttp.onreadystatechange = function () {
            if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
                console.log(xmlhttp)
                console.log(xmlhttp.response)
            }
        }

封裝：

function ajax(options){
            var xmlhttp = new XMLHttpRequest();
            if(options.dataType == 'POST'){
                var sendUrl = options.url;
                var params = options.params;
                xmlhttp.open(options.dataType,sendUrl, true);
                xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
                if(typeof params != 'string'){
                    var paramsString = new String();
                    var paramsKeys = Object.keys(params);
                    paramsKeys.forEach((item,key)=>{
                        paramsString += item +'='+ params[item] + (key!=(paramsKeys.length-1)?'&':'')
                    })
                    params = paramsString;
                }
                xmlhttp.send(params)
            }
            if(options.dataType == 'GET'){
                var sendUrl = options.url + options.params;
                xmlhttp.open(options.dataType, sendUrl, true);
                xmlhttp.send(null)
            }
            xmlhttp.onreadystatechange = function() {
                if (xmlhttp.readyState==4 && xmlhttp.status==200){
                    console.log(xmlhttp.response)
                }
                
            }
        }

        ajax({
            url:'http://127.0.0.1:6767/api/v1/login',
            dataType:"POST",
            params:{'name':'admin'},
            success: function(res){  // 請求成功的回調函數
                console.log(JSON.parse(res)); 
            },
            error: function(error) {}  // 請求失敗的回調函數
        })

JSONP:

var script = document.createElement("script");
        script.type = "text/javascript";
        script.src = "http://127.0.0.1:6767/api/v1/jsonp?callback=succersCallback";
        document.body.appendChild(script);
function succersCallback(data){
    console.log(data)
    console.log('執行')
}