386310 - attaching anonymous element to HTML via XBL prevents display of elements attached via javascript

Status: RESOLVED FIXED

(Core :: XBL, defect)

Description

[Tal Shalif]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.4) Gecko/20061201 Firefox/2.0.0.4 (Ubuntu-feisty)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.4) Gecko/20061201 Firefox/2.0.0.4 (Ubuntu-feisty)

Using XBL binding: Appending (prepending/prefixing) and anonymous html element before the <children/> of a bound HTML element in an HTML document makes it impossible to insert/wrap via javascript text contents of the bound element. 

The post-load javascript inserted element (e.g. a <span> element) is properly added to the HTML DOM, but is not displayed. Checking the calculated display and visibility rules for the 'disappeared' element do not show any reason why it is not displayed..

Reproducible: Always

Steps to Reproduce:
1. Copy following HTML to a file - e.g. bindme.html:
<script type="text/javascript">
  function onLoad() {
  var elm = document.getElementById("bound");
  var r = document.createRange();
  r.setStart(elm.lastChild, 14);
  r.setEnd(elm.lastChild, 14 + 4);
  r.surroundContents(document.createElement("span"));
  }
  window.addEventListener("load", onLoad, false);
</script>
<div id="bound" style="-moz-binding: url('bindme.xml#bindme')">one two three four</div>

2. copy following to a file named bindme.xml, under same directory as bindme.html created in step 1 above:
<bindings xmlns="http://www.mozilla.org/xbl"
         xmlns:html="http://www.w3.org/1999/xhtml">

  <binding id="bindme">
    <content>
      <html:img src="chrome://browser/skin/Throbber.gif"/>
      <children/>
    </content>
  </binding>
</bindings>
3. open the file bindme.html in firefox (make sure javascript is enabled)
4. notice how the word 'four' is not displayed?
Actual Results:  
[IMG]one two three

Expected Results:  
[IMG]one two three four

If the javascript code in the above example was to run before XBL binding takes effect (i.e. before the document completed loading), the SPAN element and its contents will be displayed properly.

Comment 1

[Tal Shalif]

Attachment: XBL binding

BL binding for attached bug-recreation case

Comment 2

[Tal Shalif]

Attachment: HTML example

HTML source for attached bug-recreation case

Comment 3

[Tal Shalif]

Attachment: CSS source

CSS source for attached bug-recreation case

Comment 4

[Tal Shalif]

There is some kind of workaround this problem:
Creating and appending as first child a non-anonymous comment element to 'this' from withing the <constructor> of the binding rule will result in the proper display of the later-inserted SPAN element (see the workaround rule in the attached XBL binding exampe)

Comment 5

[Boris Zbarsky [:bzbarsky]]

This somehow got fixed on the trunk by the checkin for bug 323098, I think (at least it got fixed that day, and that's the most likely-looking change there).  Not sure how.  In any case, the problem is not present on trunk. 

I'll get the test checked into the regression tests.

Comment 6

[Boris Zbarsky [:bzbarsky]]

I spoke too soon.  The text is there, but not in the right place.  I've added the tests, anyway, but I suspect that fixing bug 307394 will be needed to fix this.

Comment 7

[Boris Zbarsky [:bzbarsky]]

Fixed by checkin for bug 307394.  Flagged the tests as passing now.