A snippet to make jPlayer volume bar draggable.

jplayer.draggable.js

$('.jp-volume-bar').mousedown(function() {
	var parentOffset = $(this).offset(),
      width = $(this).width();
  $(window).mousemove(function(e) {
    var x = e.pageX - parentOffset.left,
    volume = x/width
		if (volume > 1) {
			$("#JPID").jPlayer("volume", 1);
		} else if (volume <= 0) {
			$("#JPID").jPlayer("mute");
		} else {
			$("#JPID").jPlayer("volume", volume);
			$("#JPID").jPlayer("unmute");
		}
	});
	return false;
})
.mouseup(function() {
  $(window).unbind("mousemove");
});

JohnnyOutdoors, replace
$(".jp-play-bar").css("width", barValue + "%");
to
$("#player").jPlayer( "playHead", barValue );