Skip to: Navigation | Content | Sidebar | Footer

Weblog Entry

Mozilla Background Transparency Bug

April 13, 2003

I’m having a rather difficult time believing I’m the first one to encounter this, but some pretty deep Googling and searching of the Bugzilla database isn’t turning up any prior mention of it.

When using a transparent GIF as a background image in an absolutely–positioned div, Mozilla does some pretty radical colour shifting. I’ve had this happen on more than one occasion, but I only looked into it a little further today.

update (4/14): — it’s been brought to my attention that this bug has been fixed by Mozilla v1.4. Great news for future releases, but Netscape 7 is still buggered unfortunately.

Reader Comments

paul says:
April 13, 08h

that’s happened to me a bunch of times. i couldn’t understand why mozilla was showing imgs with different RGB values.

Dave says:
April 13, 09h

If it looks like a bug, and it smells like a bug…

While we’re at it, I wish Mozilla would actually animate animated GIFs on rollovers. For example, my fade-inny projects buttons top right.

I guess at least there are work-arounds for the transparency issue, ie. dropping the transparency. Hurts to do it though.

Dave says:
April 14, 05h

Ack. No way I’d go to that length for animated rollovers. They’re a nicety, not a necessity.

Then again, K10k is the same site that sniffs your browser and spits out PNGs or GIFs depending on alpha support. Those guys are animals.

haze says:
April 14, 09h

when it comes to animated gifs that only play once, NS (4 and 7) play it at the very beginning when the page JUST loads up. it’ll play once, then it wont play anymore. if you use javascript to do rollovers, it’ll swap the animated gif, but it will swap the gif that has already played.

IE is a little different in that it’ll restart and replay the animated gif every single time the gif has been called. but this doesnt include MAC and PC bc MAC IE (mixed with javascript) completely messes up the sequence of the frames in the animated gif, making the animation looked fcked out.

NS4 plays animated gifs that fastest, second place is IE, while NS7 and moz are slow-ass playaz. why all these browsers need to be such retarded fools?

to solve this problem (and i personally find this an absolute OVERKILL of a solution), dont use animated gifs. instead, use javascript that will play a sequence of gifs. that way, the javascript controls the speed, what is seen, and how it’s played. i believe k10k does this, but it is bloated, superfluous code.

Dave S. says:
April 22, 03h

Sherif — quite. I don’t test anything I do in 256 colour mode anymore.

Thanks for the testing results though, I’ll add them to the page this evening.

April 22, 06h

Hmmm, no such problem in Phoenix 0.5, or Mozilla 1.3 on Windows 2000. Display color depth set to 16bit (64,000 colors) and to 24 bit (millions of colors). Are you sure you didn’t accidentally have your color depth set to 8 bit (256 colors) ;-)?