---
title: WebUndefined
framework: webkit
role: symbol
role_heading: Class
path: webkit/webundefined
---

# WebUndefined

WebUndefined objects are simply used to represent the JavaScript “undefined” value in methods when bridging between JavaScript and Objective-C. For example, if you invoke a JavaScript function that returns the JavaScript “undefined” value, then a WebUndefined object is returned to the Objective-C calling context.

## Declaration

```swift
class WebUndefined
```

## Topics

### Initializers

- [init(coder:)](webkit/webundefined/init(coder:).md)

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSCoding](foundation/nscoding.md)
- [NSCopying](foundation/nscopying.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)

## See Also

### Incorporating Scripts (Legacy)

- [WebScriptObject](webkit/webscriptobject.md)
- [WebScripting](objectivec/webscripting.md)