Promise实现ajax

 ???function getAjax(url) { ???????return new Promise((resolved,rejected)=>{ ???????????//创建ajax对象 ???????????let ajax = new XMLHttpRequest(); ???????????//配置参数 ???????????ajax.open(‘get‘,url,true) ???????????//发送请求 ???????????ajax.send(); ???????????//请求成功之后 ???????????ajax.onload = function () { ???????????????if(this.status === 200){ ???????????????????console.log(ajax.responseText) ???????????????????resolved(ajax.responseText); ???????????????}else{ ???????????????????rejected(); ???????????????} ???????????} ???????}) ???}

 ???function postAjax(url,param) { ???????return new Promise((resolved,rejected)=>{ ???????????//创建ajax对象 ???????????let ajax = new XMLHttpRequest(); ???????????//配置参数 ???????????ajax.open(‘post‘,url,true); ???????????//设置请求头，表示我传递的参数的类型 ???????????xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); ???????????//发送请求，并将数据传递过去 ???????????ajax.send(JSON.stringify(data)); ???????????//请求成功之后 ???????????ajax.onload = function () { ???????????????if(this.status === 200){ ???????????????????console.log(ajax.responseText) ???????????????????resolved(ajax.responseText); ???????????????}else{ ???????????????????rejected(); ???????????????} ???????????} ???????}) ???}

 ???function myAjax(type,url,params) { ???????return new Promise((resolved,rejected)=>{ ???????????//创建ajax对象 ???????????let ajax; ???????????//注意，不要根据浏览器的navigator.userAgent来检测浏览器是否支持某个JavaScript特性，一是因为这个字符串本身可以伪造，二是通过IE版本判断JavaScript特性将非常复杂。 ???????????if (window.XMLHttpRequest) { ???????????????ajax = new XMLHttpRequest(); ???????????} else { ???????????????ajax = new ActiveXObject(‘Microsoft.XMLHTTP‘); ???????????} ???????????if(type == ‘get‘ || type == ‘‘){//get ???????????????//配置参数 ???????????????ajax.open(‘get‘,url,true) ???????????????//发送请求 ???????????????ajax.send(); ???????????}else if(type == ‘post‘){//post ???????????????//配置参数 ???????????????ajax.open(‘post‘,url,true); ???????????????//设置请求头，表示我传递的参数的类型 ???????????????xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); ???????????????//发送请求，并将数据传递过去 ???????????????ajax.send(JSON.stringify(data)); ???????????} ???????????//请求成功之后 ???????????request.onreadystatechange = function (){ ???????????????if (request.readyState === 4){ ???????????????????if(this.status === 200){ ???????????????????????console.log(ajax.responseText) ???????????????????????resolved(ajax.responseText); ???????????????????}else{ ???????????????????????rejected(); ???????????????????} ???????????????} ???????????} ???????}) ???}