window onerror捕捉頁面異常事件

window.onerror捕捉頁面異常事件，使用這個方法可以上報埋點，便於問題的定位。上報內容：頁面信息、報錯信息

window.onerror = function (msg) {
      console.log(msg)
    }
    console.log(aa)
    // Uncaught ReferenceError: aa is not defined
// onError.html:10 Uncaught ReferenceError: aa is not defined
//    at onError.html:10