Pointless features add to browser bloat and insecurity

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. ®