// The client event FormatValueLabel takes two parameters sender and e
// sender is the object which is raising the event
// e is the SliderFormatValueLabelEventArgs
function WebSlider1_FormatValueLabel(sender, e) {
var slider = $find("WebSlider1");
//Gets format used for value labels
var valuelabelFormat = slider.get_valueLabelFormat();
window.status = "The format of the ValueLabel is " + valuelabelFormat;
//Gets suggested value for label
var label = e.get_label();
//Gets value to format as object
var value = e.get_value();
}