718321 - Lazy loading destroys anchor links to other pages

Status: VERIFIED FIXED

(support.mozilla.org :: Knowledge Base Software, task, P1)

Description

[Thomas Schwecherl]

The lazy loading of images (Bug 632809) has some annoying side effects for localizers (fast article/preview scrolling is now more time consuming because for example during scrolling in a preview of an article the images will be loaded and the article text is pushed down from new loaded images; you have to correct your position in an article/preview till all images were fully loaded). But this is only a matter for contributors.

Now I've found a problem with archor links: clicking it will open the new article but the anchor position will be lost because of lazy loading of images.

Steps to reproduce:
1. Go to https://support.mozilla.org/en-US/kb/what-firefox-sync
2. Click on the links "Where can I find my Recovery Key?" at the bottom of the article (https://support.mozilla.org/en-US/kb/how-do-i-manage-my-firefox-sync-account#w_where-can-i-find-my-recovery-key)
3. First you will see the right article section but then the rest of the images will be loaded and the section is lost ... you are anywhere in the article!

Or see the attached video:
1. German article https://support.mozilla.org/de/kb/was-ist-firefox-sync is loaded
2. At the bottom of the article, link "Wo finde ich meinen Wiederherstellungs-Schlüssel?" is clicked (engl. "Where can I find my Recovery Key?", link to https://support.mozilla.org/de/kb/wie-verwalte-ich-mein-firefox-sync-benutzerkonto#w_wo-finde-ich-meinen-wiederherstellungs-schlakssel)
3. Then the article is loading and you can't see the right section
4. The right section must be found manually - or you do another click in the address bar to jump to the anchor link again

Comment 1

[Thomas Schwecherl]

16 seconds video (as mentioned in comment 0):
http://dl.dropbox.com/u/666578/Lazy%20loading%20destroys%20anchor%20links.ogv

Comment 2

[Kadir Topal [:atopal]]

The annoyance for contributors is tracked in bug 718451. This however breaks anchored links for all users.

Comment 3

[Tanay Gavankar [:tgavankar]]

I'm treating this bug as only the fact that if you go to an anchor link on a page that has images above it, the images get "lazyloaded" and the scroll position becomes displaced (meaning you have to rescroll to find the position).

Lazyloading automatically loads all the images above the viewers current scroll point, and then loads images below it depending on how many pixels away it is.

I think a solution would be to simply have it reposition the scroll to the selected anchor tag after it loads all the images above it.

Comment 4

[Tanay Gavankar [:tgavankar]]

Done in https://github.com/mozilla/kitsune/commit/663d946.

Comment 5

[Rebecca Billings [:rbillings]]

Please add QA steps for verification.

Comment 6

[Tanay Gavankar [:tgavankar]]

Go to an article that has images before an anchor link, and go to the anchor link. The images above it should now be correctly loaded, and the scroll position should be at the anchor link (as stated in comment 0).

Comment 7

[Rebecca Billings [:rbillings]]

Verified to the best of my ability, however I was having trouble finding kb articles with anchor links and images- and the article and link in Comment 0 has been changed on stage:

https://support.allizom.org/en-US/kb/where-can-i-find-my-firefox-sync-key
https://support.mozilla.org/en-US/kb/how-do-i-manage-my-firefox-sync-account#w_where-can-i-find-my-recovery-key

Comment 8

[Verdi [:verdi] Best to slack me]

I filed bug 706479 which this seems to be a duplicate of. Regardless, the problem has not been fixed so I'm reopening. 

STR:
1. Go to https://support.mozilla.org/en-US/kb/Options window - Advanced panel
2. Once the page is loaded, reload with shift-reload to make sure you don't have any of the images further down the page loaded.
3. Click on the link to the Encryption tab in the TOC.

Expected result: Encryption tab heading is at the top of the viewport. Actual result: Offline Web Content and User Data heading was the closest to the top of the viewport in my case, your mileage may vary.

Comment 9

[James Socol [:jsocol, :james]]

Please don't re-open verified bugs. If a bug has made it to VERIFIED we should file a new one to track the work.