用promise函数封装AJAX

        用promise封装AJAX的代码如下：

        封装代码：

function myaxios(url) {
    var p1 = new Promise(function (n1, n2) {
        var xhr = new XMLHttpRequest() || new ActiveXObject("Microsoft.XMLHTTP")
        xhr.open("GET", url, true)
        xhr.send()
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4 && xhr.status == 200) {
                n1(xhr.responseText)
            } else if (xhr.readyState == 4 && xhr.status == 404) {
                n2(xhr.responseText)
            }
        }
    })
    return p1
}

        调用时的方法：

"fn()">ajax请求
 
    <script>
        function fn() {
            var url = "http://192.168.0.114:8081/ajax1" //要请求的目标网址
            myaxios(url).then((res) => {
                console.log(res);
            })
        }
    script>