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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. ®

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