# 异常监控
* 前端错误的分类
* 错误的捕获方式
* 上报错误的基本原理
## 1、前端错误的分类
* 即时运行错误：代码错误
* 资源加载错误
## 2、错误的捕获方式
### 即时运行错误捕获方式
1. try...catch
2. window\.onerror
### 资源加载错误
1. object.onerror
2. performance.getEntries
3. Error事件捕获
* 资源加载错误事件不会冒泡，只会在本身这个object报错事件进行响应
* performace.getEntries()这个API获取所有资源的加载地址
* Error事件捕获
```markup
```
### 跨域资源加载错误
1. 在script标签增加crossorigin属性（客户端错误）
2. 设置JS资源响应头Access-Control-Allow-Origin:\*（服务端做）
## 3、错误监控
* 上报错误的基本原理
* 使用Ajax通信进行上报
* 利用Image对象上报
```markup
```
---
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