js AJAX

let xhr = new XMLHttpRequest();
xhr.open("get","http://120.76.31.111/app/XhlGetSubjectTypeList");
xhr.send();
xhr.addEventListener("readystatechange",()=>{
    if(xhr.readyState==4&&xhr.status){
        let res = JSON.parse(xhr.responseText);
        console.log(res);
        renderData(res)
    }
})