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.
Not part of any specification. This is a proprietary pseudo-element specific to WebKit/Blink.
No compatibility data found. Please contribute data for "css.selectors.-webkit-slider-thumb" (depth: 1) to the MDN compatibility data repository.