# http/ws-on-message
Register a callback for incoming messages on a WebSocket connection.
## Syntax
[http/ws-on-message $conn $fn]
## Parameters
- `$conn` — `ws_conn` resource
- `$fn` — closure invoked with a `%{ :type :text|:binary :data "..." :conn }` map
## Examples
[http/ws-on-message $conn {|msg| echo $msg~type $msg~data }]
## Returns
`nil`.
## See Also
`http/ws-on-close`, `http/ws-connect`, `http/ws-server`