封装一个 jQuery.ajax jQuery.ajax(url,method,body,success, fail) 满足这种 API。
window.jQuery.ajax=function(url,method,body,successFn,failFn){letrequest=newXMLHttpRequest()request.open(method,url)request.onreadystatechange=()=>{if(request.readyState===4){if(request.status>=200&&r