Abandoment to blame for the last JavaScript file not always being loaded?

Question

I have a code snippet for an app that users are loading as a 3rd party script on their site. The general sequence is as follows:

1. Site loads http://www.example.com/foo.js
2. foo.js does stuff
3. 1 to 2 seconds later, foo.js loads bar.js

Now in a perfect world, I'd want to see matching counts for the calls to foo.js and bar.js. However, bar.js loads only about 94% of the time. I'm wondering how much of this discrepancy might be attributable to site abandonment given the fact that bar.js is delayed by 1 or 2 seconds.

I posted here instead of StackOverflow since I think it's more a question about what would be typical time on page when users abandon the page.

Answer 1

• Some users probably click away before the page fully loads
• Some users have connection problems for the second request
• Browsers without JS support or with JS disabled
• Maybe security settings? These files are both being loaded from he same domain right?
• Maybe there's a bug in the JS that's preventing some browsers from loading the second file. Is there a correlation with browser type/version?
• Web spiders

Answer 2

Some percentage of this is probably browsers that don't support JavaScript or just have JavaScript disabled.

Web crawlers would never hit bar.js for instance... (although most of them would probably have also skipped foo.js too...)