javascript detection

[Thomas Fischer <fi...@seitenbau.net>]

Hi all,

We have a project where we would like to use javascript if it is enabled in
the user's browser, but allow a fallback if javascript is disabeld, along
the lines of
http://mail-archives.apache.org/mod_mbox/myfaces-users/200708.mbox/%3c12098603.post@talk.nabble.com%3e

At the moment, we are content to do this manually, like e.g
<c:choose>
  <c:when test="${javascriptEnabled}">
    <!-- commandLink does not work without javascript -->
    <h:commandLink...>
  </c:when>
  <c:otherwise>
    <!-- commandButton works without javaScript -->
    <h:commandButton ...>
  </c:otherwise>
</c:choose>

In the myfaces configuration in web xml, I stumbled across the
org.apache.myfaces.DETECT_JAVASCRIPT setting, which sounds like it could be
used to do javascript detection. Checking the source code, the relevant
method is org.apache.myfaces.shared_impl.renderkit.html.util.
JavascriptUtils.isJavascriptDetected(). This method checks the session
variable org.apache.myfaces.shared_impl.renderkit.html.util.JavascriptUtils
.JAVASCRIPT_DETECTED to see whether javascript is detected, but this
session variable is (according to our research) never set by myfaces.

So the question is what is the intended use of the
org.apache.myfaces.DETECT_JAVASCRIPT setting ? Should the application set
the associated session variable manually ?

Assuming that the answer is "yes", would it make sense to check this
automatically ? The idea would be to render additional javascript in the
h:form component which sets a http request parameter, and to check if the
request parameter is there when the form is submitted. If the request
parameter appears, javascript is switched on, if not, it is switched off.
The problem with this would be that the very first page would have to work
without javascript, as one server round trip is needed to check the
outcome.

If there is interest in this, I'd offer to create a patch.

    regards,

      Thomas

Re: javascript detection

[Mike Kienenberger <mk...@gmail.com>]

Thomas,

Gracefully-degrading javascript support sounds like an excellent
addition to MyFaces.  The topic has come up before in the last couple
of weeks.

However, I'm not entirely certain if DETECT_JAVASCRIPT is still being
honored in MyFaces these days.   You'll probably need to implement it
where it's not being handled correctly.   I'm assuming that you're
also probably only going to handle this for MyFaces Core at first --
dealing with it for Tomahawk will probably require a great deal more
effort as each individual component will have to be reviewed and dealt
with.

On 8/20/07, Thomas Fischer <fi...@seitenbau.net> wrote:
>
> Hi all,
>
> We have a project where we would like to use javascript if it is enabled in
> the user's browser, but allow a fallback if javascript is disabeld, along
> the lines of
> http://mail-archives.apache.org/mod_mbox/myfaces-users/200708.mbox/%3c12098603.post@talk.nabble.com%3e
>
> At the moment, we are content to do this manually, like e.g
> <c:choose>
>   <c:when test="${javascriptEnabled}">
>     <!-- commandLink does not work without javascript -->
>     <h:commandLink...>
>   </c:when>
>   <c:otherwise>
>     <!-- commandButton works without javaScript -->
>     <h:commandButton ...>
>   </c:otherwise>
> </c:choose>
>
> In the myfaces configuration in web xml, I stumbled across the
> org.apache.myfaces.DETECT_JAVASCRIPT setting, which sounds like it could be
> used to do javascript detection. Checking the source code, the relevant
> method is org.apache.myfaces.shared_impl.renderkit.html.util.
> JavascriptUtils.isJavascriptDetected(). This method checks the session
> variable org.apache.myfaces.shared_impl.renderkit.html.util.JavascriptUtils
> .JAVASCRIPT_DETECTED to see whether javascript is detected, but this
> session variable is (according to our research) never set by myfaces.
>
> So the question is what is the intended use of the
> org.apache.myfaces.DETECT_JAVASCRIPT setting ? Should the application set
> the associated session variable manually ?
>
> Assuming that the answer is "yes", would it make sense to check this
> automatically ? The idea would be to render additional javascript in the
> h:form component which sets a http request parameter, and to check if the
> request parameter is there when the form is submitted. If the request
> parameter appears, javascript is switched on, if not, it is switched off.
> The problem with this would be that the very first page would have to work
> without javascript, as one server round trip is needed to check the
> outcome.
>
> If there is interest in this, I'd offer to create a patch.
>
>     regards,
>
>       Thomas
>
>