This code is placed on the sliding knob movie (the red slider in the middle)

// The following is a line by line explanation of the above.

onClipEvent(load) {
This code uses the clip events of a movie clip on stage.
//_root.vbase._height=200;
//_root.vbase._x=34;
//Optionally, use the above to set the height and x position of the slider base.

this._y = _root.vbase._y + _root.vbase._height/2 - this._height/2;
//This sets the knob exactly in the middle of the vbase.

left=this._x
// This will keep the knob from moving any further left.

top= this._y + _root.vbase._height/2
// This set the upper limit that the knob can be moved.

right=this._x
//This keeps the knob from moving any further right.

bottom=this._y - _root.vbase._height/2
//This keeps the knob from moving any further down than half the height of vbase.

volCalc=_y+ _root.vbase._height/2;
// This set the variable volCalc to equal the knob's current position
// plus half of the height (whatever it may be) of the vbase.
}
//End of onClipEvent load
//
onClipEvent(enterFrame) {
volCalc2=(_y-volCalc)*(-100/(_root.vbase._height));
// Thanks, prisma for help with the above line. This take the current knob position
//subtracts the value of volCalc, and multiplies it by -100 divided by the height of vbase.

_root.myMusic.setVolume(volCalc2);
// Sets the new volume level

_root.currentVolumeText="Volume: " + _root.myMusic.getVolume();
// Update a dynamic text box

this.onPress = function() {
startDrag(this, false, left, top, right, bottom);
}
//uses the values set in the load clip event to constrain the knob movement to set values.

this.onRelease = function() {
this.stopDrag();
}
// "this" refers to the slider knob. The code is placed in the actions panel for the slider knob, vslider.

}//End of onClipEvent enterFrame