> For the complete documentation index, see [llms.txt](https://yuzhigang5460.gitbook.io/electron/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yuzhigang5460.gitbook.io/electron/tutorial/online-offline-events.md).
# 在线/离线事件检测
在渲染器进程中,使用标准HTML5 API实现在线和离线事件检测,例子:
*main.js*
```javascript
const {app, BrowserWindow} = require('electron')
let onlineStatusWindow
app.on('ready', () => {
onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false })
onlineStatusWindow.loadURL(`file://${__dirname}/online-status.html`)
})
```
*online-status.html*
```markup
```
你也许会希望在主程序中回应这些事件,但由于主进程中不存在`navigator`对象，所以无法直接检测在线还是离线。
不过,你可以使用Electron的进程间通信方法将事件进行转发到主进程进行处理，例子:
*main.js*
```javascript
const {app, BrowserWindow, ipcMain} = require('electron')
let onlineStatusWindow
//ready时启用监听
app.on('ready', () => {
//隐藏窗口载入渲染进程,以便获取通信状态
onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false })
onlineStatusWindow.loadURL(`file://${__dirname}/online-status.html`)
})
//主进程中从渲染进程通信的网络状态
ipcMain.on('online-status-changed', (event, status) => {
console.log(status)
})
```
*online-status.html*
```markup
```
**注意:** 除了Electron未连接局域网(LAN)或路由器被视为离线(脱机)之外,其他条件都返回 `true`。
尽管如此,当 `navigator.onLine` 返回一个 `false`值时,你不能想当然的以为 `true`即已联网,因为联网状态可以轻易伪造,比如计算机使用虚拟化软件始终连接着虚拟以太网网络适配器.
所以,如果要确定 Electron的真实联网状态，您应该使用更多检查手段。
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