1636084 - USPS.com package tracker appears to stall for several seconds during page load, with custom tracking protection settings

Status: RESOLVED WORKSFORME

(Web Compatibility :: Site Reports, defect, P3)

Description

[Nathan Froyd [:froydnj]]

Basic information

Steps to Reproduce:

1. Load https://tools.usps.com/go/TrackConfirmAction_input (Firefox Nightly)

Expected Results:

Page loads rapidly.

Actual Results:

There's a noticeable pause of several seconds after the reload button repaints and the browser appears to be doing nothing, presenting the user with a white screen.

---

More information

Profile URL: https://perfht.ml/2SMZYhk

Basic systems configuration:

OS version: Linux Ubuntu 16.04

GPU model: Radeon R9 270

Number of cores: 6

Amount of memory (RAM): 64GB

Thanks so much for your help.

Comment 1

[Markus Stange [:mstange]]

I cannot reproduce this on my machine - the page becomes visible quickly, both with and without adblocker, and both with and without tracking protection.

In the profiler, I can see a setTimout handler that runs at the end, which presumably makes the web content visible. Apparently that setTimeout was kicked off with an interval of 137738ms (just over 2 minutes): "setTimeout callback — setTimeout handler with interval 137738ms: A (https://www.gstatic.com/recaptcha/releases/wk6lx42JIeYmEAQSHndnyT8Q/recaptcha__en.js:289)" https://perfht.ml/2WU19wB
I also see some network requests that just seem to be waiting for the server for a long time.
I'm not sure why the website would intentionally hide the content until the timeout. We've seen cases before where a website would hide its content until either some particular resource loaded, or a timeout fired. And then tracking protection blocked that resource and we would wait for the timeout. Maybe something similar is going on here?

Nathan, is this still happening for you? Can you get a profile with URLs in a fresh Firefox profile?

Comment 2

[Nathan Froyd [:froydnj]]

Ah, so it doesn't reproduce for me in a fresh-ish profile, but if I set my ETP settings to "custom" and block things in all windows, rather than just private browsing ones, I see the slowdown. Do those settings work for you?

Comment 3

[Markus Stange [:mstange]]

Yes, I can reproduce this with those settings!

Comment 4

[Mike Taylor [:miketaylr]]

Tom, something for you to look at?

Comment 5

[Thomas Wisniewski [:twisniewski][PTO August 18-22]]

It's asynchide:

  <!-- Optimize Page Hiding Snippet -->
  <style>.async-hide { opacity: 0 !important} </style>
  <script>(function(a,s,y,n,c,h,i,d,e){s.className+=' '+y;h.start=1*new Date;
  h.end=i=function(){s.className=s.className.replace(RegExp(' ?'+y),'')};
  (a[n]=a[n]||[]).hide=h;setTimeout(function(){i();h.end=null},c);h.timeout=c;
  })(window,document.documentElement,'async-hide','dataLayer',4000,
  {'GTM-T35N9RL':true});</script>
<!-- end Optimize Page Hiding Snippet -->

The related shim I'm working on in bug 1637329 seems to do the trick here.

Comment 6

[Oana Arbuzov [:oanaarbuzov]]

I can't reproduce the issue on my side, with any ETP setting (Strict/Custom/Standard/Disabled), the page loads fast.
ETP - Custom: (1.31s) https://prnt.sc/yu7air
ETP - Strict: (914ms) https://prnt.sc/yu7f65
ETP - Standard: (1.50s) https://prnt.sc/yu9a4p
ETP - Disabled: (926ms) https://prnt.sc/yu9gjf

Tested with:
Browser / Version: Firefox Nightly 87.0a1 (2021-02-09)
Operating System: Windows 10 Pro, Ubuntu 20.4

Nathan can you still reproduce it?