##
slider.setStopFunc()

    function f(s) {
        var v = s.getValue()
        // do something with v, the current value of slider s1 or s2
    }
    var s1 = new slider
    var s2 = new slider
    s1.setStopFunc(f)
    s2.setStopFunc(f)

Sets the function that is called when the slider button stops moving. The first parameter to the function is the slider object that triggered it. This slider's "getValue()" method gives the actual value of the slider when it did the function call. This function is called both when the slider button has been dragged, and when the slider has been clicked in a different place.