is there any possibility to add a css selector for lower part of input[type=range]? or is there any reason why it is not desirable?
mozilla's workaround is -moz-range-progress, for IE/Edge you have -ms-fill-lower, but there is no workaround for webkit browsers (except the js + gradient, what is too heavy for such an easy thing).
IMHO: make -webkit-progress-value applicable to input[type=range] and it is enough :)
thanks a lot