Closed Bug 1117220 Opened 5 years ago Closed 3 years ago - unresponsive script when changing font and adding bullet to new compose


(Web Compatibility :: Desktop, defect)

Firefox 33
Not set


(platform-rel ?)

Tracking Status
platform-rel --- ?


(Reporter: guigs, Assigned: karlcow)




(Whiteboard: [sitewait] [microsoft] [js] [country-all] [platform-rel-Microsoft][platform-rel-Outlook])


(2 files)

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:35.0) Gecko/20100101 Firefox/35.0
Build ID: 20141208150535

Steps to reproduce:

1. Sign into an account at
2. go to live mail (
3. Click the +New to compose a new message
4. Add a cc and a title
5. Start to type some text in the email
6. Add a bullet list with the icon
7. Click on the Font button and change it to Arial
7. hit enter at the end of the line of the first bullet

Actual results:

There was a warning for an unresponsive script: 
[POST [HTTP/1.1 200 OK 282ms]
no element found ScenarioQos.mvc:1
Error in parsing value for 'font-size'.  Declaration dropped. RteFrameResources.aspx
POST [HTTP/1.1 200 OK 62040ms]
Error: Script terminated by timeout at:

Expected results:

There not to be an unresponsive script
Problem occurs here too. Something to do with mutation events and jQuery going into an endless loop. 

Might be as simple as this code:

t.prototype._onNodeInserted = function (n) {
    var i = n.srcElement,
    i.tagName == 'FONT' && (r = i.getAttribute('size'), = t.getFontSizes() [r - 1])

Running from a DOMAttrModified listener causes a new DOMAttrModified event to fire.
$B.Firefox && (t.prototype._doInitImpl = function () {
    this._onNodeInsertedHandler = $CD(this, this._onNodeInserted);
    var t = n(this._editor);
    t.on('DOMNodeInserted', this._onNodeInsertedHandler);
    t.on('DOMAttrModified', this._onNodeInsertedHandler);

The thing I don't quite understand yet is that _onNodeInserted method seems to set style.fontSize to undefined every time it runs (getAttribute('size') returns null, null - 1 is -1 and r.getFontSizes()[-1] is undefined). The DOMAttrModified runs because the style attribute is removed, it makes some sense that this removal happens due to setting undefined - but again and again? Is there some code elsewhere that sets fontSize to a good value?
The _onNodeInserted method in the code for Safari looks pretty different.
I also see Firefox fire DOM Mutation events that IE doesn't. (Chrome and Safari do not seem to support DOMAttrModified at all).

I'll upload a demo showing different behaviour in Firefox and IE, but it seems the root cause here is the browser sniffing in the JS and that the code Firefox gets hasn't taken this specific corner case into account. There are at least two simple fixes if my analysis is correct (I haven't changed the JS to test this): one is to bail out if getAttribute('size') returns null, the other one is to return early if it's a DOMAttrModified event and attrChange is 3 (deleted attribute).
Given that DOM mutation events are deprecated anyway it probably doesn't make sense to spend time on figuring out whether Firefox or IE implementation is spec-compliant (if the spec covers this in the first place, that is).
Whiteboard: [contactready] [microsoft]
Assignee: nobody → kdubost
Contacted through email our contact at Microsoft.
Whiteboard: [contactready] [microsoft] → [sitewait] [microsoft] [js] [country-all]
Could someone with an outlook account test again?
Still an issue - please nag them :)
Whiteboard: [sitewait] [microsoft] [js] [country-all] → [sitewait] [microsoft] [js] [country-all] [platform-rel-Microsoft][platform-rel-Outlook]
platform-rel: --- → ?
ni? mike to test again.
Flags: needinfo?(miket)
It seems like this no longer reproduces, possibly due to a redesign.
Flags: needinfo?(miket)
Closed: 3 years ago
Resolution: --- → WORKSFORME
Product: Tech Evangelism → Web Compatibility
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