JSF and JavaScript can combine their forces to develop powerful applications. For example, let's see how we can use JavaScript code with h:commandLink and h:commandButton to obtain a confirmation before getting into action.
We have developed this recipe with NetBeans 6.8, JSF 2.0, and GlassFish v3. The JSF 2.0 classes were obtained from the NetBeans JSF 2.0 bundled library.
As you know the h:commandLink takes an action after a link is clicked (on the mouse click event), while h:commandButton does the same thing, but renders a button, instead of a text link. In this case, we place a JavaScript confirmation box before the action starts its effect. This is useful in user tasks that can't be reversed, such as deleting accounts, database records, and so on.
Therefore, the onclick event was implemented as shown next:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>JSF and JavaScript example</title>
</h:head>
<h:body>
<!-- using h:commandLink and JavaScript -->
<h:form id="myCLForm">
<h:commandLink id="cmdlinkID" value="Delete record"
onclick="if (!confirm('Are you sure you want to delete the
current record?')) return false"
action="#{bean.deleteRecord}"/>
</h:form>
<!-- using h:commandButton and JavaScript -->
<h:form id="myCBForm">
<h:commandButton id="cmdbtnID" value="Delete record"
onclick="if (!confirm('Are you sure you want to delete the
current record?')) return false"
action="#{bean.deleteRecord}"/>
</h:form>
</h:body>
</html>
Notice that we embed the JavaScript code inside the onclick event (you also may put it separately in a JS function, per example). When the user clicks the link or the button, a JS confirmation box appear with two buttons. If you confirm the choice the JSF action takes place, while if you deny it then nothing happens.