May 6, 2008
In the course of the development of the
Web Paint-by-Number site and various other
of experimentation with different browsers to figure out how they handle
The results have generally been nightmarish,
with truly impressive ranges of bizarre and strange behavior.
These pages summarize my results in a few areas, mainly having to do with
I wrote them up largely for my own future reference.
I have found very little of this information available elsewhere on the web.
on all browsers. In practice, this is only possible if you are willing
give up a lot of functionality. Many of the features used in the Web
Paint-by-Number site would have been impossible in implement without
first sensing the browser type and then selecting different code to run
for different browsers, or different versions of the same browser.
Sad, but true.
Worse, due to bad design and shear bugginess,
there are perfectly simple things that cannot be reliably done on
some browsers, like identifying with certainty which key was pressed to
trigger a keydown event or recognizing when the second
click of a double-click occurs.
If you are a programmer trying to sort these things out, you might consider
of them can help insulate you from this kind of low-level headaches described
in this page.
Surveying such toolkits is beyond the scope of these pages, however.
All the programs and code fragments that I have written for these pages can be
treated as being in the public domain, free of copyright, OK to use in
any way without any legal restrictions. You are encouraged to apply the
information and techniques described here anywhere you find them useful
The text of the articles themselves are all copyrighted by Jan Wolter, however.
You can also take it as given that I offer all the code and information on
these pages without warranty or guarantee of it's correctness or suitability
for use. So don't sue me.
- Mouse Events
- Madness in the handling of mouse events. Which events are fired
when you click or double-click with the left, right or middle
mouse button on various browsers.
- Key Events
- Madness in the handling of keyboard events. Which events are fired
when you hit or release a key or allow it to auto-repeat in various
The demented strangeness of key codes which may or may not identify
which key was hit.
- Dynamic Script Loading
on demand after the rest of the page has already been loaded.
As usual, many browser incompatibilities are discovered.
function that other languages use to pause execution for a bit?
Yes, it can be done, but only horribly.
- Treacherous Type Conversions
- A (hopefully informative) rant about string/number type
- Layout Engines and Gecko Versions
- Why I talk about "Gecko" instead of "Firefox" in the above notes.
Which versions of Gecko are used by various
browsers and a few notes on other layout engines.
- Parsing Query Strings
and decoding functions.
Ill-Informed Grousing About Browsers
For years I have used this section to vent my annoyance at all these
While other people touted their favorite browsers, I'd grown to dislike
them all for various reasons and in various degrees.
But things have changed.
Browsers have actually gotten pretty good at supporting the basic needs of
It's kind of astonishing.
- Internet Explorer
For a very long time,
Internet Explorer has been the leading source of headaches for web developers.
IE started out buggy and incompatible, and then
development pretty much stopped between 2000 and 2006.
While other browsers got better, the one most people used just kept stinking.
Virtually all web developers got to hate it, because everything had to be
carefully programmed to work around all it's bugs.
But then a miracle happened.
As far as I can tell, Internet Explorer 9 is a fully capable modern browser,
that supports the core standards as competently as any of it's competitors.
It's actually OK.
It really is.
My brain can't quite grasp it, but it seems to be true.
Long ago the Netscape browser introduced many of
the key innovations that made browsers cool, but Netscape went
bust and the Mozilla foundation picked up the pieces to rebuild
that musty old code into the leading open source browser.
The Mozilla developers generally proceed at a rather plodding pace.
They are hardly ever the first, but they keep up.
Minor bugs often seem to take years to get fixed,
but new releases rarely introduce new bugs.
The Mozilla developers never seem to participate in the
races to be the first and the fastest that periodically
break out between the Safari and Opera teams.
When Mozilla releases a new browser, I don't expect to see as many
exciting changes as in a new Opera or Safari,
but I don't expect to see major new bugs introduced either.
Once Firefox was just one of many browsers using Mozilla's Gecko rendering
engine, but while others still exist, the have increasingly fallen by the
New browsers these days are more likely to be based on Webkit than Gecko.
This used to be the browser that causes me the least headaches.
If you wrote code to work on IE and Firefox, then it pretty much always
worked on Safari. Up through version 3.0 there were lots of signs of very
careful thought going into their design choices,
clear attempts to balance compatibility with sanity.
In terms of compatibility and correctness, Safari seemed to have
overtaken everything else.
Then it seemed like
their competitive exuberance began getting the best of them.
For example, they greatly hyped their new faster regular expressions, but
they weren't always as fast as the hype suggested
and they were sufficiently buggy that I had to entirely rewrite my most
complex regex application not to use regular expressions anymore.
This hasty, benchmark-driven development style, this race to be first and
fastest, risks undermining an otherwise terrific browser.
Chrome uses the same open source rendering engine as Safari, so for my purposes
it is mostly the same.
It's most notable for a very fast release cycle.
This is the browser that has caused me the most headaches over the years.
When Mozilla's developers seem mired in bureaucracy, and
Microsoft's developers are only just finding their desks again after a
seven year vacation,
Opera's developers was always speedy and nimble.
Every release was different from the last. Old bugs turn into
different bugs, new bugs are introduced, and sometimes a
bug is even fixed.
Every bug I ever reported to them was changed in a subsequent release,
though generally they were not actually fixed for a long time.
I sometimes wished they would slow down and figure out how things are supposed
to work instead of patching patches.
Tracking what did and did not work in Opera was a constant
But, as with IE, recent versions have pretty much settled down to a fairly
good approximation of correctness.
- This browser is a lot better than one would reasonably expect from
something with so little visibility.
Safari and Chrome were derived from it,
but the relationship doesn't always show.
In mouse and key event handling, they are very different.
It doesn't always seem like the fixes Apple makes get back to the
- Netscape 4
- Obviously nobody uses this anymore.
It is sometimes included in these reports because it was the source of
many defacto standards that newer browser more or less emulate,
so it gives a little historical context to all this that can help
make more sense of it all.
- Ah, the simple pioneer days. I remember them well.
I should go back to Mosaic, and stop worrying.
This page renders great in Mosaic.