No-JavaScript notes


 * Please edit/overhaul/merge elsewhere freely.

I was asked about the demographics of no-JavaScript users, and didn't have a great or solid answer ("Corporate intranet users? old-browser users? users avoiding banner ads?"), so I went looking. Here's what I found:

Reasons for disabling JavaScript
Users may intentionally receive the non-JavaScript version, because:
 * Security
 * For security - (javascript vulnerabilities in browsers)
 * For privacy - (preventing some tracking/advertising systems, usually coupled with disabled-Cookies)
 * Corporate proxy disabled it - (for intranet security)
 * Preference
 * For annoyance prevention - (to prevent things like animations, particularly for users who find these overwhelmingly distracting)
 * Performance
 * For faster site downloading - (less to download (bytes))
 * For faster browser rendering - (less to calculate (complexity))

Users may unintentionally receive the non-JavaScript version, if:
 * They lost connection to the internet midway through the page-load - (especially mobile users, and users with unstable wifi connections)
 * Some JavaScript code throws an exception during initialization, preventing futher code from loading

Methods for disabling JavaScript

 * NoScript, uMatrix, and similar browser extensions
 * Browser settings (e.g.  option in Firefox)
 * Connection proxy
 * A browser that doesn't support it - (lynx, etc)
 * Developers can use their browser's developer tools to disable JavaScript for specific requests

Tips for developers

 * MediaWiki has  and   classes that CSS can use to target users based on whether JavaScript is run for them.
 * Use your browser's developer tools to test user interfaces without JavaScript enabled

Metrics

 * Global:
 * 2010: 1.6% average (2.06% in U.S., 0.26% in Brazil) (according to developer.yahoo.com)
 * 2013: 1.1% in U.K. (according to gds.blog.gov.uk
 * (newer stats, and other Reliable sources, would be appreciated. Statcounter doesn't yet reveal no-JS usage)
 * Internal
 * 2015: ~3% per Analytics/Reports/Clients without JavaScript
 * 2016: ~7% per File:Browsers, Geography, and JavaScript Support on Wikipedia Portal.pdf and File:Analysis of Wikipedia Portal Traffic and JavaScript Support.pdf

Sources and good links

 * http://www.punkchip.com/2011/03/why-support-javascript-disabled/
 * https://stackoverflow.com/questions/337570/is-it-worth-it-to-code-different-functionality-for-users-with-javascript-disable
 * https://stackoverflow.com/questions/9478737/browser-statistics-on-javascript-disabled
 * http://webaim.org/projects/screenreadersurvey5/#javascript
 * https://gds.blog.gov.uk/2013/10/21/how-many-people-are-missing-out-on-javascript-enhancement/
 * http://halls-of-valhalla.org/beta/articles/javascript-disabled-should-i-care,49/
 * https://sonniesedge.co.uk/blog/a-day-without-javascript - "Like a good friend, Wikipedia never disappoints. The site is indistinguishable from the JS version. Keep being beautiful, Wikipedia."
 * Progressive enhancement
 * Unobtrusive JavaScript
 * WebAIM on accessible javascript and the myth that people disable JavaScript due to accessibility concerns