---
title: onchecking
framework: webkitjs
role: symbol
role_heading: Instance Property
path: webkitjs/domapplicationcache/1634093-onchecking
---

# onchecking

Sent when the cache update process begins.

## Declaration

```data
attribute EventHandler onchecking;
```

## See Also

### Handling Events

- [onerror](webkitjs/domapplicationcache/1629048-onerror.md)
- [onnoupdate](webkitjs/domapplicationcache/1631877-onnoupdate.md)
- [ondownloading](webkitjs/domapplicationcache/1632146-ondownloading.md)
- [onprogress](webkitjs/domapplicationcache/1631599-onprogress.md)
- [onupdateready](webkitjs/domapplicationcache/1629348-onupdateready.md)
- [oncached](webkitjs/domapplicationcache/1632145-oncached.md)