[jsr-314-open] sendAjaxRequest is not defined?

I have this: <h:inputText value="#{user.name}"...> <f:ajax event="onkeyup" render="echo"/> </h:inputText> .. <h:outputText id="echo" value="#{user.name}"/> That works fine. As I type in the input, whatever I type is echoed by the output. But if I remove the event attribute, like this: <h:inputText value="#{user.name}"...> <f:ajax render="echo"/> </h:inputText> .. <h:outputText id="echo" value="#{user.name}"/> For the preceeding markup, nothing is echoed as I type, or when I tab out of the field. In fact, the only thing that happens is that I get a JS error that says "sendAjaxRequest is not defined". Is this a bug? I've attached a snapshot of the error in Firebug. Thanks, david