封装ajax

1. 封装

var ajax = {
            getxhr: function() {
                return new XMLHttpRequest();
            },
            get: function(url, fun, sync=true) {
                var xhr = this.getxhr();
                xhr.onreadystatechange = function() {
                    if(xhr.readyState == 4) {
                        fun(xhr.responseText);
                    }
                }
                xhr.open('get', url, sync);
                xhr.send();
            },
            post: function(url, data, fun, sync=true) {
                var xhr = this.getxhr();
                xhr.onreadystatechange = function() {
                    if(xhr.readyState == 4) {
                        fun(xhr.responseText);
                    }
                }
                xhr.open('post', url, sync);
                xhr.send(data);
            }
        }

2. 使用

document.getElementById('id').onclick = function() {
            ajax.get('127.0.0.1:8000/gets', true, function(data) {
            	alert(data);
            );
        };