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 ::-ms-expand CSS pseudo-element represents the button within a <select> that opens or closes the drop-down menu that displays the list items specified in <option> elements. It normally looks like a triangle that points downward.




Not part of any specification.

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 Last updated by: chrisdavidmills,