CSS Sticky Scrollbars

A Collection of Interesting Ideas,

This version:
http://tabatkins.github.io/css-sticky-scrollbars/
Issue Tracking:
GitHub
Editor:
Tab Atkins (Google)

Abstract

Scrollbars that "stick" to an edge!

1. This Spec Has Been Superseded

This spec has been superseded by other CSS technology. In particular, to implement a chatroom that "sticks" the scrollbar to the bottom of the scroller when you’re near the bottom, staying there if you add new messages to the bottom, but not messing with your scroll position when you’re scrolled elsewhere in the history, just use [css-scroll-snap-1]:

.message-container {
  scroll-snap-type: proximity;
}
.message-container::after {
  content: "";
  height: 0;
  overflow: hidden;
  display: block;
  scroll-snap-align: end;
}

This creates a single scroll snap area in the message container, aligned with the very bottom of the container. If you scroll "near" the bottom, you’ll snap to it; if you add more content to the message container (thus pushing the ::after further down), it’ll automatically re-snap to it (because scroll containers have to re-snap to the same scroll snap area if it still exists); if you are scrolled somewhere else in the history, it won’t do anything at all.

The use-case of "stable scrolling", where you want "whatever you’re currently looking at" to stay on the screen when things are added/removed/resized higher up in the scroll container, is handled by the Scroll Anchoring proposal currently making its way thru the standards process.

Conformance

Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology. The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this document are to be interpreted as described in RFC 2119. However, for readability, these words do not appear in all uppercase letters in this specification.

All of the text of this specification is normative except sections explicitly marked as non-normative, examples, and notes. [RFC2119]

Examples in this specification are introduced with the words “for example” or are set apart from the normative text with class="example", like this:

This is an example of an informative example.

Informative notes begin with the word “Note” and are set apart from the normative text with class="note", like this:

Note, this is an informative note.

Index

Terms defined by reference

References

Normative References

[CSS-OVERFLOW-3]
David Baron; Florian Rivoal. CSS Overflow Module Level 3. URL: http://drafts.csswg.org/css-overflow/
[CSS-SCROLL-SNAP-1]
Matt Rakow; et al. CSS Scroll Snap Module Level 1. URL: https://drafts.csswg.org/css-scroll-snap-1/
[RFC2119]
S. Bradner. Key words for use in RFCs to Indicate Requirement Levels. March 1997. Best Current Practice. URL: https://tools.ietf.org/html/rfc2119