[IPOL discuss] javascript in demos [Re: BM3D ready in dev. server]

Fri Apr 29 11:32:33 CEST 2011

Hi,

> It's true that the Run button doesn't work without Javascript. With this
> demo this is easy to fix, although for the noise estimation demo we need
> some Javascript to make it work.

Javascript is required for the noise estimation demo? I don't
understand why. To me, javascript in this demo seems to be only used
to show or hide the "number of bins" form field. You can achieve the
same functionnality by always displaying the two form controls
                    ____                          _
   number of bins: |____| or automatic selection |_|

or even without the checkbox
                    ____ 
   number of bins: |____| (0 for automatic selection)

If javascript doesn't bring a clear improvement to the page usability,
it should not be used, because no code means no bug.

> Anyway, the sliders also need Javascript to work because of the
> JQuery.

Yes, sliders need javascript, but without javascript the page is still
usable because we can still fill the form field with the keyboard and
run the demo.

> Is there a real and important reason to avoid using Javascript in the
> demos? Almost all the users use browsers with Javacript enabled.

Simplicity. To keep ipol easy to manage, develop and maintain, we have
to keep it simple. IPOL already uses many technogical layers:
* C/C++ (and make/cmake) for the executable algorithms 
* Python (with some extension modules) for the demo engine
* HTTP+HTML+CSS for the web interaction

Of course there always is a balance to find between simplicity and
functionnality. We decided to use javascript when it brings some
usability improvements, as discussed in the slider and image selection
messages on this list.

Most of our users have Javascript-capable browsers, and Javascript
support is now much better than the crippled browser-dependant
situation we had, say, 5 years ago. But there still are some
differences between major browsers, so adding javascript to an ipol
demo still is another potential bug source and requires cross-browser
testing.
-> http://en.wikipedia.org/wiki/Comparison_of_web_browsers#JavaScript_support
-> http://en.wikipedia.org/wiki/Acid3#Browsers_that_do_not_pass

Some users disable javascript in their browsers and enable it on a
per-site basis, because of the security and privacy implications of
having javascript running, and because javascript is often used to
insert adds in web pages and trigger pop-ups, which some people don't
want.

So, I think IPOL demos should still be usable without javascript, in
degraded mode. And if for some demo we absolutely want javascript and
can't design an alternative no-js mode, then the demo pages must
display a warning message when javascript is not enabled. Without this
warning, users reaching the demo witout javascript can't understant
why the demo doesn't work.

You will find at the end of this mail the browser statistics for IPOL
since he beginning of the year. This only counts javascript-enabled
browsers. I just modified the statistics settings to start gathering
informations about non-javascript browsers, and I will post them on
the list after a few weeks.

8<----------

nb_visits	pc_visits	browser
8715		34.20		Firefox 3.6
2890		11.34		IE 8.0
2143		8.41		Chrome 10.0
1648		6.47		Chrome 8.0
1574		6.18		Chrome 9.0
1283		5.03		Safari 5.0
1270		4.98		Firefox 4.0
927		3.64		IE 7.0
914		3.59		Firefox 3.5
913		3.58		IE 6.0
496		1.95		Opera 11.01
457		1.79		Firefox 3.0
343		1.35		Safari 4.0
274		1.08		Opera 11.00
225		0.88		Chrome 6.0
198		0.78		Chrome 11.0
169		0.66		IE 9.0
126		0.49		Chrome 7.0
109		0.43		Safari 4.1
108		0.42		Opera 11.10
79		0.31		Chrome 12.0
66		0.26		Firefox 2.0
59		0.23		SeaMonkey 2.0
58		0.23		Chrome 5.0
39		0.15		Opera 10.63
35		0.14		Android 4.0
35		0.14		Konqueror 4.5
32		0.13		Opera 10.01
27		0.11		Opera 10.54
23		0.09		Unknown
22		0.09		Firefox 1.5
19		0.07		Chrome 4.1
17		0.07		Chrome 3.0
12		0.05		Opera 9.64
11		0.04		Chrome 13.0
10		0.04		Konqueror 3.5
9		0.04		Epiphany 5.0
8		0.03		Firefox 6.0
8		0.03		Iron 10.0
7		0.03		Opera 9.62
6		0.02		Iron 8.0
6		0.02		Chrome 4.0
6		0.02		SeaMonkey 1.0
6		0.02		Opera 10.10
6		0.02		Opera 10.62
5		0.02		Chrome 2.0
4		0.02		Opera 10.60
4		0.02		Opera 10.61
4		0.02		SeaMonkey 1.1
4		0.02		Iron 9.0
3		0.01		Firefox 1.0
3		0.01		Chrome 1.0
3		0.01		Netscape 5.0
3		0.01		Opera 9.02
3		0.01		Konqueror 4.6
3		0.01		Safari 3.0
3		0.01		BlackBerry 6.0
2		0.01		Firefox 4.2
2		0.01		SeaMonkey 1.9
2		0.01		OmniWeb 5.10
2		0.01		Flock 2.6
2		0.01		Konqueror 4.4
2		0.01		Firefox 3.1
2		0.01		Opera 9.63
2		0.01		Opera 10.00
2		0.01		Mozilla 1.7
2		0.01		Firefox 0.8
1		0.00		BlackBerry 9300.0
1		0.00		SeaMonkey 2.1
1		0.00		Epiphany 1.0
1		0.00		IE 12.00302
1		0.00		Safari 5.1
1		0.00		Camino 2.0
1		0.00		BlackBerry 8520.0
1		0.00		Opera 8.01
1		0.00		BrowseX 2.0
1		0.00		Opera 9.25
1		0.00		Konqueror 3.4
1		0.00		Opera 9.5
1		0.00		Opera 10.11
1		0.00		Opera 9.51
1		0.00		BlackBerry 9700.0
1		0.00		IE 999.1
1		0.00		Opera 9.80
1		0.00		Firefox 10.00241
1		0.00		Opera 9.22
1		0.00		Opera 10.53
1		0.00		Opera 9.50
1		0.00		Opera 9.26
1		0.00		Iron 5.0
1		0.00		Flock 3.5
1		0.00		IE 4.01
1		0.00		Flock 2.5
1		0.00		Opera 9.52
1		0.00		Safari 3.1
1		0.00		iCab 2.9
1		0.00		Phoenix 2.08
1		0.00		Epiphany 2.22
1		0.00		Netscape 10.6

-- 
Nicolas LIMARE - CMLA - ENS Cachan    http://www.cmla.ens-cachan.fr/~limare/
IPOL - image processing on line                          http://www.ipol.im/
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