204961 - Apply XBL bindings before interpreting JavaScripts?

Status: RESOLVED WONTFIX

(Core :: XBL, defect)

Description

[Alex Vincent [:WeirdAl]]

Note attachment 122801 [details] (zipped testcase) from bug 204957.

The testcase, by opening the nsScriptAttrTest.xml file, uses XBL to insert an
alert before the comment in the second script (html > head > script).  The
inserted alert does not currently run through the interpreter.

If the XBL bindings applied before the scripts entered the interpreter, it would
allow for modifying one script which in and of itself isn't compatible with
Mozilla into another which is (a la XML Events, under Handlers, section 3.3)

For instance, XML Events gives the following example:

<script type="application/x-javascript"
        ev:event="submit" ev:observer="form1">
   return docheck(event);
</script>

With a little care, that could transform into:

<script type="application/x-javascript"><![CDATA[
document.getElementById("form1").addEventListener("submit", function(event) {
   return docheck(event);
}, false);
]]></script>

See bug 164482 for progress on XML Events.

Comment 1

[Alex Vincent [:WeirdAl]]

Actually, it'd be:

<script type="application/x-javascript"><![CDATA[
document.getElementById("form1").addEventListener("submit", function(event) {
]]>
<![CDATA[
   return docheck(event);
]]>
<![CDATA[
}, false);
]]></script>

Comment 2

[Hixie (not reading bugmail)]

I don't really think this is the right way to go. Hyatt?

Comment 3

[Boris Zbarsky [:bzbarsky]]

I don't think we should do this -- the content of script is not a presentational
or behavioral property of the script, really...

Comment 4

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

I would be fine with doing this unless it affects performance, and if someone
steps up to the plate to do this. I don't however think that we should
implements xml-events in this way, i'd rather see a "real" implementation in C++

Comment 5

[Boris Zbarsky [:bzbarsky]]

> unless it affects performance

Doing this will, if nothing else, force script evaluation at frame construction
time instead of content creation time...  that will require that all scripts
always flush the content sink (to ensure that the frames get constructed right
there and then).

So yes, it will hurt performance of loading vanilla HTML pages.

Comment 6

[Hixie (not reading bugmail)]

I really don't think it is semantically right to expect XBL to affect compiling
of scripts. At all. :-)

Comment 7

[Boris Zbarsky [:bzbarsky]]

Right.  That was comment 3.

With sicking and Ian's leave, WONTFIX.