发送请求后，取消请求
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
#result {
width: 300px;
height: 100px;
border: 1px solid red;
}
</style>
</head>
<body>
<button>点击发送</button>
<button>点击取消</button>
</body>
<script>
//当用户点击发送请求后，突然进行了其他操作，则中断请求
const btm = document.querySelectorAll('button');
let x = null;
btm[0].onclick = function(){
x = new XMLHttpRequest();
x.open('GET','http://127.0.0.1:8000/delly');
x.send();
}
btm[1].onclick = function(){
x.abort()
}
</script>
</html>
