How can I execute Javascript before a JSF <h:commandLink> action is performed? [duplicate]

Question

If you have a JSF <h:commandLink> (which uses the onclick event of an <a> to submit the current form), how do you execute JavaScript (such as asking for delete confirmation) prior to the action being performed?

Answer 1

Can be simplified like this

onclick="return confirm('Are you sure?');"

Answer 2

<h:commandLink id="myCommandLink" action="#{myPageCode.doDelete}">
    <h:outputText value="#{msgs.deleteText}" />
</h:commandLink>
<script type="text/javascript">
if (document.getElementById) {
    var commandLink = document.getElementById('<c:out value="${myPageCode.myCommandLinkClientId}" />');
    if (commandLink && commandLink.onclick) {
        var commandLinkOnclick = commandLink.onclick;
        commandLink.onclick = function() {
            var result = confirm('Do you really want to <c:out value="${msgs.deleteText}" />?');
            if (result) {
                return commandLinkOnclick();
            }
            return false;
        }
    }
}
</script>

Other Javascript actions (like validating form input etc) could be performed by replacing the call to confirm() with a call to another function.

Answer 3

This worked for me:

<h:commandButton title="#{bundle.NewPatient}" action="#{identifController.prepareCreate}"  
                                             id="newibutton" 
                                             onclick="if(confirm('#{bundle.NewPatient}?'))return true; else return false;" 
                                             value="#{bundle.NewPatient}"/>