IE8 tile loading bug

[Trufi]

Can you look at leaflet (master branch) in IE8? Tiles sometimes freeze and stop loading after several drags and zooms. It looks like:

Windows XP, Service Pack 3, IE8

[perliedman]

I can reproduce this with latest master on IE8/Win7 (virtual machine from MS in Virtual Box) with the /debug/map/map.html example.

An interesting question is if Leaflet still aims to support IE8, which starts to get really old, and it seems some libraries are dropping support for it.

I'll try to have a look, but given the state of IE8 debugger, I can't promise anything :)

[mourner]

Yeah, Leaflet still has to support IE8 since A LOT of government/enterprise apps depend on this. Thanks for looking into this.

[perliedman]

Follow up: I ran the test specs on IE8, and there are quite a few errors. Some of them appear in GridLayer, which I guess might be the issue we're seeing here.

[perliedman]

So far, I've found out that the tiles load, but for some reason the leaflet-tile-loaded class is never applied to the element. I'll try to find some more time to dig into why.

As a side note, this issue can be debugged in IE11 if you set the debugger's document mode to IE8, which makes things a lot easier.

[osvodef]

I think I've managed to pinpoint the bug, here is a possible solution: #3346

[mourner]

@RLRR thanks a lot! Merged.