The correct answer is that -webkit-box
and -moz-box
are the two you need to use for the 2009 syntax. display: box
w/o prefix should not be used, as it was never implemented by any browser.
A syntax with prefixes like -webkit-box
is always the early implementation of a specs by a browser. The prefixed rule always comes first before the final standard.
As discussed here or here. The full proper syntax of the main container (for all browsers) is:
.flex-container {
display: -webkit-box; /* Safari 3.1 - 6, Chrome < 21 (2009 Spec), UC Browser Android */
display: -moz-box; /* Firefox 2 - 27 (2009 Spec), UC Mini */
display: -ms-flexbox; /* IE10 (2012 Syntax) */
display: -webkit-flex; /* Safari 6.1 - 8, Android < 4.4, BB < 10, Chrome 21 - 28 */
display: flex; /* Edge 12+, Firefox 28+, Blink, Safari 9+, Opera Mini 8+ */
}