document.readyState == 'interactive' is invalid DOM ready test in IE10

[shogun70]

This relates to a bug in the v2.0 branch.

/complete|interactive/.test(document.readyState) and document.onreadystatechange are not reliable as DOM ready tests. All versions of IE can have interactive state before the DOM is fully loaded. Also, readystatechange can fire before the DOM is fully loaded.

I have written an exploratory test which is sufficient to confirm this bug.

https://gist.github.com/shogun70/5388420

The jQuery project also has a bug report -
document ready is fired too early on IE 9/10
and a "fix" -
sometimes IE10 and lower have document.readyState == "interactive" way too early

domReady also has a report and fix -
Add Guard for invalid readyState in IE9 and IE10

[shogun70]

Also, Opera doesn't fire the readystatechange event on document.

CORRECTION: document.onreadystatechange fires after window.onload.
I've updated the test:
https://gist.github.com/shogun70/5388420

[jansepar]

@shogun70 thanks for the test case! I will look into this and come up with the appropriate fix asap!

[shogun70]

Unlike DOMContentLoaded and readystatechange, window.onload is supported on all recent and almost all older browsers. When mobify.js is able to run on older browsers then a window.onload solution won't need to be updated.

Because there is no content, images or styles to download and / or render, I would assume that window.onload is not significantly later than any other event that could be used.