AJAX

const ajax = (method,url,data,success,fail)=>{
    const xhr = new XMLHttpRequest()
    xhr.open(method,url)
    xhr.onreadystatechange = ()=>{
        if(xhr.readyState === 4){
            if(xhr.status >= 200 && xhr.status < 300 || xhr.status === 304){
                success(xhr)
            }else{
               fail(xhr)
            }
        }
    }
    xhr.send(data)
}