css Audio - Active file-generic CSS - Active Generic - Active HTML - Active JS - Active SVG - Active Text - Active file-generic Video - Active header Love html icon-new-collection icon-person icon-team numbered-list123 pop-out spinner split-screen star tv
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This Pen is a fork of Jonathan Snook's Pen mxOVzB.


  1. With Webkit, you can just apply a transition to the value element.

  2. Legit use of CSS variables :)

  3. FWIW, and yeah I realize you said you were targeting the latest browsers, but this doesn't animate in Firefox 56. It still falls back to a functional version though, identical to the non-animated version.

  4. @pdowling Hey, just getting to this comment. It should work in latest Firefox. (Most of the battle was making it work in Firefox.)

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