EnotionZ/iDropper — comment on commit 3cd911d95507691c19c4f6e7faedb8e72e863aca
File: iDropper.css line 148
By EnotionZ:

Lol.. I could've phrased that better.. I meant that Base64 syntax alone works for my use case, not for a general use case. Lemme explain

That data URI is a 1x1px transparent png. It's applied to an element which completely overlaps an image.

This is to fix a problem in all IEs where, even if an element overlaps another, without content or some kind of background on it, the event target we get back is the element beneath it. Sidenote: since the data URI is already there, it doesn't really hurt for that transparent image to be applied as a background in other browsers (although I thought I had changed it so the transparent background only gets applied to IE now. Maybe I didn't commit it yet).

Now in IE7, that syntax will yield a "broken" image, but because of this, the transparency factor remains, AND it gets rid of the event target issue because there IS a "transparent background image" (of sort).
IE6 isn't quite as graceful because the target will still be the underlying element. That's irrelevant thought since I'm already using AlphaImageLoader on the overlapping element so the target I get back is still accurate.

I suppose the source deserves that documentation, I just didn't think anyone would dig into it. Haha