JSF f:ajax listener vs commandButton action

Question

I'm curious what is the difference between these two ways of executing ajax calls:

<h:commandButton value="Submit" action="#{bean.action}">
   <f:ajax execute="@form" render="component"/>
</h:commandButton>

and

<h:commandButton value="Submit">
   <f:ajax listener="#{bean.action}" execute="@form" render="component"/>
</h:commandButton>

It appears that people use the first way more often, but the second seems to work just fine as well...

Answer 1

The first way allows for navigation by returning a String outcome and the second not. The second way won't invoke anything if the client has JS disabled, while the first way gracefully degrades. Indeed, the first way is used more often.

The second way is the only way in components which doesn't have an action attribute, such as <h:selectOneMenu> and so on.