h:commandLink - 'onclick' encoding

Question

I've noticed a deficiency in the JSF specification regarding the encoding of the 'onclick' attribute of the <h:commandLink> component:
[http://java.sun.com/javaee/javaserverfaces/1.2/docs/tlddocs/h/commandLink.html]
[http://java.sun.com/javaee/javaserverfaces/2.0/docs/pdldocs/jsp/h/commandLink.html]
[http://java.sun.com/javaee/javaserverfaces/2.0/docs/pdldocs/facelets/h/commandLink.html]
All of these state:
Encode Behavior
If an "onclick" attribute was specified by the user, render this JavaScript in a function, and render the user's JavaScript in a function. Render both functions in a choice function as follows:
var a=function(){#USER_FUNCTION#}; var b=function(){#JSF_FUNCTION#}; return (a()==false) ? false : b();
where #USER_FUNCTION# is the user's JavaScript and #JSF_FUNCTION# is the JavaScript rendered by JSF. The choice function should operate such that if the user's JavaScript returns true, then the rendered JavaScript will also execute.Anyone familiar with JavaScript executed in a browser knows the event handlers are executed a bit differently than normal functions. So the 'this' reference in event handlers refers to the element the handler has been registered on, like:
<a href="..." onclick="window.alert(this.href);">...</a>Invoking a function in the normal way "resets" the 'this' reference to the global object, i.e. the 'window', so:
<script type="text/javascript">
  function testAlert() {
    alert(this.href);
<a href="..." onclick="testAlert();">...</a>no longer works as expected. The same happens with the JSF specified way of handling user specified 'onclick' script:
<h:commandLink value="Try me!" action="..." onclick="window.alert(this.href);" />would render:
<a href="#" onclick="var a=function(){window.alert(this.href);}; var b=function(){#JSF_FUNCTION#}; return (a()==false) ? false : b();">Try me!</a>The user code in the above example would 'alert' an undefined value and not the expected 'href' of the link element. The problem is when one wants to pass the original 'this' reference to the element to a function for additional processing but this reference gets lost because of the JSF specification. It is really trivial to have this done correctly and causing no confusion to newcomers (like me), as:
var a=function(){#USER_FUNCTION#}; var b=function(){#JSF_FUNCTION#}; return (a.call(this)==false) ? false : b();Note the a.call(this) vs. a() call. This would preserve the 'this' reference in the #USER_FUNCTION# code, would be more natural to everyone (no difference between writing the code in a plain HTML link element or JSF h:commandLink) and would be just better. I hope someone will address this issue in next JSF revision. It is currently very irritating if not a buggy behavior.

Answer 1

You have raised a very interesting and valid point. However, this is probably not the best venue to get the message to the people that need to hear it. I would suggest bringing it up on the Mojarra developers mailing list ( [https://javaserverfaces.dev.java.net/mailinglists.html|https://javaserverfaces.dev.java.net/mailinglists.html] ).