Check if images loaded using Promises starting with the code in this answer: https://codereview.stackexchange.com/a/128619/181592
No-Library (pure JS), HTML, CSS, JavaScript
Figuring out Promises once and for all.
Testing page visibility API, but it only knows if you switch tabs, not windows.
Page visibility test of code from: https://stackoverflow.com/a/1060034/1024735
Autolinker.js test 20190507
jQuery 3.3.1, HTML, CSS, JavaScript
Mootools 1.3.2, HTML, CSS, JavaScript
jQuery 2.1.3, HTML, CSS, JavaScript
Testing flexible layout options for GTAskD.
GTaskD testing promises 3
GTaskD testing promises 2