compose-multiplatform/tutorials/Web/Events_Handling

Events handling in Compose Web

The API is experimental, and breaking changes can be expected

You can add event listeners in the attrs block:

onClick

Button(
    attrs = {
        onClick { wrappedMouseEvent -> 
            // wrappedMouseEvent is of `WrappedMouseEvent` type    
            println("button clicked at ${wrappedMouseEvent.movementX}, ${wrappedMouseEvent.movementY}")
            
            val nativeEvent = wrappedMouseEvent.nativeEvent // [MouseEvent](https://developer.mozilla.org/en/docs/Web/API/MouseEvent)
        }
    }
) {
    Text("Button")
}

onInput

val text = remember { mutableStateOf("") }

TextArea(
    value = text.value,
    attrs = {
        onTextInput { wrappedTextInputEvent ->
            // wrappedTextInputEvent is of `WrappedTextInputEvent` type
            text.value = wrappedTextInputEvent.inputValue
        }
    }
)

Your event handlers receive wrapped events that inherit from GenericWrappedEvent, which also provides access to the underlying nativeEvent – the actual event created by JS runtime - https://developer.mozilla.org/en-US/docs/Web/API/Event

There are more event listeners supported out of a box. We plan to add the documentation for them later on. In the meantime, you can find all supported event listeners in the source code.