Re: User Timing Mark Name for "Critical Content Loaded"?

Repost from GH:

For what it's worth, the "time to critical content loaded" for Firefox OS
is considered `visuallyLoaded`, since that is the core content on the page.
`navigationLoaded` is for the UI content needed to navigate the site, like
navigation bars, hamburger menus, etc.

Eli Perelman

On Wed, Jul 15, 2015 at 10:29 AM, Patrick Meenan <>

> On the Chrome side we are going to go ahead with implementing reporting
> for the 'navigationLoaded' mark and do some evangelism around it.  It's
> probably worth holding off on updating the spec until we see if there is
> uptake from developers and how useful it ends up being.
> On Thu, Jun 25, 2015 at 9:02 AM, Patrick Meenan <>
> wrote:
>> Performance observers don't really give the browser (or performance
>> tools) a better way to know about what the application developer cares
>> about.  They just give the developer a better way to track things (and
>> maybe a better way to mark the "critical content loaded" point).  I think
>> we still need an agreed-upon or convention for a mark name for Apps that do
>> care to track it to expose it in a standard way.
>> On Thu, Jun 25, 2015 at 7:57 AM, Philippe Le Hegaret <> wrote:
>>> On 06/24/2015 07:28 PM, Patrick Meenan wrote:
>>>> At least for what I was planning to do with it it wouldn't alter any
>>>> behavior.  We (and I expect most browsers) track aggregate field metrics
>>>> for a bunch of technical metrics to track our performance and guide our
>>>> optimization work.  None of the standard technical measurements really
>>>> mean anything for the user experience (onload, DOM Content Loaded,
>>>> etc).  A lot of sites have their own custom metrics that they track that
>>>> does better tie to the user experience and most that do have a core
>>>> "this is the user experience time for this operation".  The time to
>>>> first tweet and time to first pin were concrete examples that I know of
>>>> but just about every major web property has their own.
>>>> What I'd like to do is to be able to collect that in a standard way so
>>>> that when we make optimization trade-offs we take the applications
>>>> actual experience metrics into account.  That does mean that it will
>>>> impact decisions that we make about how the browser works but not in the
>>>> context of that specific page or page load.
>>> With performance observers, this would give you an easier to track those
>>> marks, correct?
>>> Philippe

Received on Wednesday, 15 July 2015 15:51:27 UTC