83 per cent of browser features are used by under one per cent of top websites
It might be time for the warlocks of the Web and brewers of JavaScript to revisit their ever-burgeoning developer wish-lists and sweep away the rubbish.
Researchers from the University of Illinois have looked at how users and Website designers respond to the feature-list, and their study suggests there’s a whole lot of kruft that nobody – site owners or end users – are using.

Or, as El Reg would put it: your browsers and Web servers are bloating with features nobody wants, and contribute nothing but extra lines of code.
As they write at Arxiv: “We find, for example, that 50 per cent of the JavaScript provided features in the web browser are never used by the top ten thousand most popular websites,” the paper states.
It’ll surprise nobody that at least some of the non-execution of features is down to site ad-blockers and the like, but the end result is: “83 per cent of available features are executed on less than 1 per cent of the most popular 10,000 websites.”
A couple of features that the researchers found provide good examples.
ALS, “ambient light events”, would let browsers respond to the light level the laptop, phone or desktop is exposed to if anybody used it.
Since 14 Websites out of the 10,000 in the study used it, and since it’s blocked by 100 per cent of blocking browser extensions, why not kill it off?
The Encoding standard would let JavaScript code read and convert between different text encodings if anyone used it, but it’s even more unloved than ALS. Nobody bothers blocking Encoding, because only one out of the 10,000 Webmasters was doing anything with it.
Iframes fall into a different category: half of the sites use iframes (because who doesn’t love a popup?), but “is prevented from being executed over 77 per cent of the time”.
All of this adds to the Web’s security woes as well, as the table below (an extract of a much larger table from the study) shows.

The study notes, “unpopular and heavily blocked features have imposed substantial security costs to the browser”.
Standard Name
Abbreviation
Features
Sites
Block Rate
CVEs in 3 years
HTML: Canvas
H-C
54
7061
33.1%
15
Scalable Vector Graphics 1.1 (2nd Edition)
SVG
138
1554
86.8%
14
WebGL
WEBGL
136
913
60.7%
13
HTML: Web Workers
H-WW
2
952
59.9%
11
HTML 5
HTML5
69
7077
26.2%
10
Web Audio API
WEBA
52
157
81.1%
10
WebRTC 1
WRTC
28
30
29.2%
8
XMLHttpRequest
AJAX
13
7957
13.9%
8
DOM
DOM
36
9088
2.0%
4
Indexed Database API
IDB
48
302
56.3%
3
Beacon
BE
1
2373
83.6%
2
Media Capture and Streams
MCS
4
54
49.0%
2
Web Cryptography API
WCR
14
7113
67.8%
2
CSSOM View Module
CSS-VM
28
4833
19.0%
1
Fetch
F
21
77
33.3%
1
Gamepad
GP
1
3
0.0%
1
High Resolution Time, Level 2
HRT
1
5769
50.2%
1
HTML: Web Sockets
H-WS
2
544
64.6%
1
HTML: Plugins
H-P
10
129
29.3%
1
Web Notifications
WN
5
16
0.0%
1
Resource Timing
RT
3
786
57.5%
1
Vibration API
V
1
1
0.0%
1
SVG, for example, has a problem however you look at it: on one hand more than 15 per cent of the sites use it, on the other hand, nearly 87 per cent of blockers block it, but it’s had 14 security warnings (CVEs, Common Vulnerabilities and Exposures) in the last three years. ®
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