JSF 2 button and commandButton example

In JSF 2.0, both <h:button /> and <h:commandButton /> tags are used to render HTML input element of type button, with different mechanism to handle the navigation.

1. JSF h:commandButton example

The “h:commandButton” tag is released since JSF 1.x, you can declare the bean, which return the navigation outcome in the “action” attribute. If browser’s with JavaScript disabled, the navigation is still working, because the navigation is handled via form post.

1. Submit button

//JSF
<h:commandButton value="submit" type="submit" action="#{user.goLoginPage}" />

//HTML output
<input type="submit" name="xxx" value="submit" /> 

2. Reset button

//JSF
<h:commandButton value="reset" type="reset" />

//HTML output
<input type="reset" name="xxx" value="reset" /> 

3. Normal button

//JSF
<h:commandButton value="button" type="button" />

//HTML output
<input type="button" name="xxx" value="button" /> 

4. Normal button with onclick event

//JSF
<h:commandButton value="Click Me" type="button" onclick="alert('h:commandButton');" />	

//HTML output
<input type="button" name="xxx" value="Click Me" onclick="alert('h:commandButton');" />

2. JSF h:button example

The “h:button” is a new tag in JSF 2.0, you can declared the navigation outcome directly in the “outcome” attribute, no need to call a bean to return an outcome like “h:commandButton” above. But, if browser’s with JavaScript disabled, the navigation will failed, because the “h:button” tag is generate an “onclick” event to handle the navigation via “window.location.href”. See examples :

1. Normal button without outcome

//JSF
<h:button value="buton" />			

//HTML output
<input type="button" 
   onclick="window.location.href='/JavaServerFaces/faces/currentpage.xhtml; return false;" 
   value="buton" /> 

P.S if the outcome attribute is omitted, the current page URL will treat as the outcome.

2. Normal button with an outcome

//JSF
<h:button value="buton" outcome="login" />			

//HTML output
<input type="button" 
   onclick="window.location.href='/JavaServerFaces/faces/login.xhtml; return false;" 
   value="buton" /> 

3. Normal button with JavaScript.

//JSF
<h:button value="Click Me" onclick="alert('h:button');" />

//HTML output
<input type="button" 
   onclick="alert('h:button');window.location.href='/JavaServerFaces/faces/page.xhtml;return false;" 
   value="Click Me" /> 

My thought…

No really sure why JSF 2.0 released this “h:button” tag, the JavaScript redirection is not practical, especially in JavaScript disabled browser. The best is integrate the “outcome” attribute into the “h:commandButton” tag, hope it can be done in future release.