Create unit test for window.load .ready() fallback

[m_gol]

I was wondering, is a fallback from document DOMContentLoaded to window load in jQuery.ready.promise still needed in jQuery 2.x? (line 789 in src/core.js on master). IE supports it from 9 but other browsers have had support for much longer time; it's also supported on old Android (at least 2.3).

This would save a few bytes if it's not needed any more.

[Rick Waldron]

Give it a shot

[m_gol]

​https://github.com/jquery/jquery/pull/1209

I've run the full test suite in current Chrome, Firefox & Safari as well as in IE9 & IE10 and all went fine (though, obviously, any bugs here might not be catched in a usual test).

I don't have any Android devices to test, though.

[dcherman]

Is it possible for jQuery to be loaded after DOMContentLoaded, but before the load event has occurred ( think RequireJS or some other script loader )?

If that's the case, then jQuery.ready would never be fired since document.readyState would be "interactive" at that point.

[mikesherov]

window.load is needed for the reason dcherman describes. A long loading iframe on a page could keep the page "interactive" if jQuery is async loaded after DomContentLoaded. Rather than remove the fallback _{maybe write a test proving its necessity?}

[m_gol]

OK, I'll try to write a test case.

[m_gol]

I updated my pull request, reverting the removal and adding a test, see there for further comments & remarks:
​https://github.com/jquery/jquery/pull/1209

[dmethvin]

Marking as open and renaming to reflect the end result since we're not removing the fallback.

[Michał Gołębiowski]

Fix #13655. Add test for jQuery.ready.promise fallback load. Close gh-1209.

Changeset: 32b066d3805a48f8c8312562ed52a1b5910b1d85