Adapt Learning Community: Slow loading time on Internet Explorer

Hi fellow Adapters!

We are experiencing some odd behaviours, when running an Adapt course in Internet Explorer. It takes a very long time to load the course when started, both when testing on our LMS, on a webserver and even directly in the Adapt preview.

Internet Explorer seems to be taking up to 3 times as long time to load as Google Chrome. I know Chrome might be faster than IE in general, but the difference in loading time usually isn’t this much for other courses we have made in the past…

The course is build using the AT and is using several of our own plugins (both extensions, menu, theme and components).

When I run the course in IE while debugging the performance, I get this graph:

I start the profiler as soon as I hit the preview button in Adapt and stops it again as soon as the “Loading…”-text disappears, and the course is ready.

Is the graph above normal? I’ve highlighted the “odd” part of the graph. To me, the graph looks like it starts loading and using a lot of CPU power at the first half of the loading time, but then it drops and uses almost no CPU power on the second half (the highlighted part of the picture).

When I dive down into one of these frames to see what the browser is doing in this “odd” section, I find:

There are a lot of Timer events, and when I click them I go to this part of the underscore.js code:

I tried putting breakpoint at this section of the code, and refreshed the course, and it turns out that this m.delay function is called by Adapt’s initialize function.

I know that the initialize function is fired many times during an execution of a course, but is this the course of the “odd” section of the graph?

I’m new to all this browser debugging, and I might just be fumbling around in the blind here, but the fact is that, sometimes our end users (using IE) have to wait a whole minute, before the course is done loading, where Chrome users (and other browser’s) only have to wait seconds. Which means that IE-users will think that the course is broken and quit, before the course is done loading…

Please help

Thank you, Henrik

What version of the Adapt framework are you using in your AT install?

Also, is this a particularly large course in terms of number of components?

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Hi Matt

"adapt_authoring": "v0.3.0",
"adapt_framework": "v2.0.16"

and yes it's a large course with many components, but I don't think that we have had problems with large Adapt courses before. I tried removing all extensions in the course, which made the loading faster on all browsers. IE was still around three times as slow as the other browsers. I haven't tried to remove any components yet, as it would take some time to do, as it should be done one by one, to see if one of them is the course to the problem.

But I just thought I would ask in here before trying to do that.

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How many components, out of interest? To save you counting them, execute the following in the console:

require('core/js/adapt').components.length;

Interestingly v2.0.16 was when we introduced this change to try and improve the performance of Adapt running in IE8, so it's possible this could have had an adverse impact... but you'd think we (Kineo) or others would have noticed, the majority of our clients have IE11 as their primary browser.

Were the other large courses you were using also on 2.0.16 or a different version?

Some other things you could try:

check out any non-core plugins you're using to see if one of them could be causing the problem
make sure your core plugins are as up-to-date as you can make them (the latest version of some will be OK with framework 2.0.16, others might need a later version). It might be easiest/safest to export source from your authoring tool then do this using the framework command line
try downloading the latest version of the framework and try dropping your course content into that to see if it works any better. you might want to play it safe initially and choose the 'legacy' branch when prompted, if you choose 'master' you'll get the very latest which is still a bit of a work-in-progress (and has no support for IE8/9/10)

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Does the issue go away when built with the latest version of the framework (found on GitHub)? Since 2.0.16, there have been performance improvements that greatly improved load times

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Hi Matt & Ryan

The course is big…

require('core/js/adapt').components.length = 315

Other courses we have been developing, have been on various versions of the Framework and AT. It could be that we never actually have developed a course, this size on a non-updated version, and thus never had the issue before.

We tried upgrading to the newest version of both the framework and AT, and now IE is just as fast as the other browsers.