I have this very simple code which works fine until I add a f:ajax tag. Code that works: <h:commandButton disabled="#{!feature.available}" class="featureButton" value="#{feature.selected ? 'selected': feature.available? 'available':'unavailable'} " style="vertical-align: top;" action="#{Bean.toggleFeature(feature)}"> </h:commandButton> Code that doesn't work: <h:commandButton disabled="#{!feature.available}" class="featureButton" value="#{feature.selected ? 'selected': feature.available? 'available':'unavailable'} " style="vertical-align: top;" action="#{Bean.toggleFeature(feature)}"> <f:ajax event="click" /> </h:commandButton> As far as I can tell the jsf.js file is loaded fine, this is automatically added by the facelet servlet to the head of my rendered document <script type="text/javascript" src="/www/javax.faces.resource/jsf.js.xhtml?ln=javax.faces"></script> and I was even able to do a jsf.ajax.request directly from javascript and got the page to rerender something. I am using mojarra 2.1.13, tomcat 7, eclipse juno, java 7. Any thoughts on what I might be doing wrong or how I might be able to troubleshoot this issue? debugging it in javascript didn't help at all. Thanks.