背代码，完整版
var request = new XMLHttpRequest()
request.open('GET', '/a/b/c?name=ff', true);
request.onreadystatechange = function () {
if(request.readyState === 4 && request.status === 200) {
console.log(request.responseText);
}};
request.send();
背代码，简化版
var request = new XMLHttpRequest()
request.open('GET', '/a/b/c?name=ff', true)
request.onload = ()=> console.log(request.responseText)
request.send()
