1.ononline:网络连通的时候触发这个事件
2.onoffline:网络断开时触发
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// 1.ononline:网络连通的时候触发这个事件
// window.οnοnline=function(){}
window.addEventListener("online", function() {
alert("网络连通了");
})
// 2.onoffline:网络断开时触发
// window.οnοffline=function(){}
window.addEventListener("offline", function() {
alert("网络断开了");
})
</script>
</body>
</html>