:-moz-system-metric(scrollbar-thumb-proportional)

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The :-moz-system-metric(scrollbar-thumb-proportional) CSS pseudo-class will match an element if the computer's user interface uses proportional scrollbar thumbs; that is, the draggable thumb on the scrollbar resizes to indicate the relative size of the visible area of the document.

This selector is intended for use mainly by theme developers.

Note: Since Firefox 58, this pseudo-class is no longer available to web content — it is only available internally (e.g. to XUL / chrome code). See bug 1396066 for more details.

Specifications

Not part of any specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
:-moz-system-metric(scrollbar-thumb-proportional)
DeprecatedNon-standard
Chrome No support NoEdge No support NoFirefox No support 3 — 58
Notes
No support 3 — 58
Notes
Notes Internal only since Firefox 58 (See bug 1396066).
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android No support 4 — 58
Notes
No support 4 — 58
Notes
Notes Internal only since Firefox 58 (See bug 1396066).
Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No

Legend

No support  
No support
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.
See implementation notes.
See implementation notes.
Related Topics
  1. CSS
  2. CSS Reference
  3. CSS Selectors
  4. Guides
    1. Using the :target pseudo-class in selectors
  5. Properties
    1. Selector list
  6. Basic Selectors
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  7. Combinators
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    3. Child combinator
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    5. Column combinator
  8. Pseudo-classes
    1. :active
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    3. :checked
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    27. :last-child
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    29. :left
    30. :link
    31. :not()
    32. :nth-child()
    33. :nth-last-child()
    34. :nth-last-of-type()
    35. :nth-of-type()
    36. :only-child
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    38. :optional
    39. :out-of-range
    40. :placeholder-shown
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    45. :root
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  9. Pseudo-elements
    1. ::-moz-progress-bar
    2. ::-moz-range-progress
    3. ::-moz-range-thumb
    4. ::-moz-range-track
    5. ::-ms-browse
    6. ::-ms-check
    7. ::-ms-clear
    8. ::-ms-expand
    9. ::-ms-fill
    10. ::-ms-fill-lower
    11. ::-ms-fill-upper
    12. ::-ms-reveal
    13. ::-ms-thumb
    14. ::-ms-ticks-after
    15. ::-ms-ticks-before
    16. ::-ms-tooltip
    17. ::-ms-track
    18. ::-ms-value
    19. ::-webkit-progress-bar
    20. ::-webkit-progress-value
    21. ::-webkit-slider-runnable-track
    22. ::-webkit-slider-thumb
    23. ::after (:after)
    24. ::backdrop
    25. ::before (:before)
    26. ::cue
    27. ::first-letter (:first-letter)
    28. ::first-line (:first-line)
    29. ::grammar-error
    30. ::marker
    31. ::part()
    32. ::placeholder
    33. ::selection
    34. ::slotted()
    35. ::spelling-error