Monitoring web sockets via wireshark?

Hi, I have built a simple html5/websocket application but I cannot seem to capture the packet data associated with any web socket connections with wireshark. Has anyone done this before? I am failing to find anything that looks like it was sent to or from the web socket server. My purpose here is to test how easy it is to monitor the contents of the packets (in the case that I want to send potentially sensitive data over the connection), and as a web developer this kind of thing is a little out of my normal scope so any help is appreciated. Thanks!