16:55:54 <RRSAgent> RRSAgent has joined #webperf
16:55:54 <RRSAgent> logging to http://www.w3.org/2013/06/26-webperf-irc
16:55:56 <trackbot> RRSAgent, make logs world
16:55:56 <Zakim> Zakim has joined #webperf
16:55:58 <trackbot> Zakim, this will be WPWG
16:55:58 <Zakim> I do not see a conference matching that name scheduled within the next hour, trackbot
16:55:59 <trackbot> Meeting: Web Performance Working Group Teleconference
16:55:59 <trackbot> Date: 26 June 2013
17:00:24 <plh> plh has joined #webperf
17:01:56 <JatinderMann> present+ JatinderMann
17:02:00 <JatinderMann> present+ AaronHeady
17:02:01 <AaronHeady> AaronHeady has joined #webperf
17:02:07 <JatinderMann> present+ RobDickenson
17:02:08 <rdickins> rdickins has joined #webperf
17:02:08 <plh> zakim, this is per
17:02:09 <Zakim> ok, plh; that matches RWC_web-per()1:00PM
17:02:10 <simonjam> simonjam has joined #webperf
17:02:50 <Zakim> + +1.650.214.aabb
17:02:50 <plh> zakim, passcode?
17:02:51 <Zakim> the conference code is 97373 (tel:+1.617.761.6200 sip:zakim@voip.w3.org), plh
17:03:04 <JatinderMann> present+ JamesSimonsen
17:03:08 <Zakim> +Philippe
17:03:15 <JatinderMann> presen+ Plh
17:04:37 <JatinderMann> Topic: Resource Priorities
17:15:30 <JatinderMann> James: At Velocity, people loved this attribute. For example, Amazon liked the idea of never loading some resources that have been lazyloaded and are not visible.
17:17:35 <plh> q+
17:19:24 <plh> q-
17:21:59 <JatinderMann> Jatinder: James, so would you never kick off the resource if it's not visible? Typically, resource are fetched in the early stages of loading a page, formatting and layout information wouldn't come in until later.
17:23:10 <JatinderMann> James: I think we would put it on a queue and if the resource hasn't been fetched and we now know the formatting/layout information, we won't kick off the resource until its visible.
17:29:48 <JatinderMann> Jatinder: I do think we still need to work out what this attribute means for <script>. Currently we were leaning towards not blocking the window onload event for lazyload scripts. However, does this mean a developer will need to register an onload handler on each script element to know when to execute the script? Or do we create a new event that indicates when all resources (including lazyloaded resources) has been loaded?
17:31:20 <JatinderMann> James: I think the pattern where developers add load events to each <script lazyload> is reasonable.
17:49:01 <plh>  https://www.w3.org/2002/09/wbs/35125/TPAC2013/
17:49:43 <Zakim> -[Microsoft.a]
17:49:46 <Zakim> -[Microsoft]
17:49:47 <Zakim> - +1.650.214.aabb
17:49:47 <Zakim> - +1.949.754.aaaa
17:49:49 <Zakim> -Philippe
17:49:49 <Zakim> RWC_web-per()1:00PM has ended
17:49:49 <Zakim> Attendees were [Microsoft], +1.949.754.aaaa, +1.650.214.aabb, Philippe
17:59:10 <JatinderMann> James: That's especially the case if we don't ever fetch a resource because we know that it's not visible. If we add a special event that fires for all resources, including lazyloaded resources when they are loaded, that event may never fire.
17:59:40 <JatinderMann> James: I think developers will use the pattern of adding an onload handler on the lazyloaded resource if they want to know when it's loaded.
18:01:15 <JatinderMann> Jatinder: On the topic of when the element is visible on the screen, if we were to fetch the resource only when it was visible, they may be a delay before the user sees it, which may be an even worse experience. Most browsers have a render region that's greater than the window size. We should leave the definition of 'visibile' loose here so that the browser can fetch the resource before the user is able to scroll to it.
18:01:45 <JatinderMann> James: I completely agree. I think we should keep this loose enough that the browser will fetch by the time it's in the rendered region.
18:02:16 <JatinderMann> Jatinder: I also don't think we should specify the exact algorithm here, especially if there are future optimizations browser vendors want to make on the render region.
19:13:48 <JatinderMann> Jatinder: On the topic of visibility, not all resources are visible resource, e.g., Audio. The purpose of this attribute is really to help the browser better organize the priority in which it downloads resources, so I don't think this is necessarily tied to visibility. I like the concept that we have one attribute that we can add to all elements capable of downloading a resource to indicate that this is a lower priority download.
19:14:11 <JatinderMann> ,,, we should consider each element on its own merit, and pull them if we don't think they should use this attribute.
19:14:18 <JatinderMann> James: I agree with that as well.
19:15:14 <JatinderMann> James:  I think we should add additional examples to the spec to make it clear that there are other cases covered here as well, not just above vs. below the fold.
19:15:57 <JatinderMann> James: I like the idea of leaving the exact algorithm that the browser uses off the spec, so to allow the browser to adapt.
19:16:03 <JatinderMann> Jatinder: I also agree that this should only be a hint.
19:16:24 <JatinderMann> Philippe: If we don't have any normative requirements, then what are we going to test? I think the spec should have some normative statements.
19:16:46 <JatinderMann> Jatinder: If we add the behavior that lazyload doesn't block the window load event, that should be a normative requirement to test.
19:17:59 <JatinderMann> Jatinder: I think we need to do a few updates the spec: add additional examples that aren't related to above/below fold, add seperate sections for each element type and define the expected behavior, and clarify loosely correlate visibility here.
19:18:32 <JatinderMann> Phiippe: There has been quite a bit of interest for an element visibility definition for Web Drivers, requestAnimationFrame, and possibly others. We spoke about this in the past.
19:19:35 <JatinderMann> Jatinder: Yes, ad vendors would be interested as well. Today they use a series of different techniques for each browser to determine if their ad is more than 50% visible. I can propose a specification here if there is interest.
19:19:44 <JatinderMann> Topic: TPAC
19:20:02 <JatinderMann> Philippe: TPAC registration has opened today. Please feel free to register for our event.
19:20:20 <JatinderMann> Philippe: Also, we can start publishing draft specs now in this working group as the charter has been updated.
19:20:26 <JatinderMann> Topic: IE11 Release Preview
19:21:20 <JatinderMann> Jatinder: IE11 Release Preview was released today. It supports Navigation Timing L2 and also an implementation of lazyload in the connection management layer. I'll send a seperate email that details the changes.
19:21:27 <JatinderMann> rrsagent, generate minutes
19:21:27 <RRSAgent> I have made the request to generate http://www.w3.org/2013/06/26-webperf-minutes.html JatinderMann
19:23:14 <Zakim> Zakim has left #webperf