Hi Sandara,

These codes look confusing to me. If you process ValueChanged event, then you may use get_isSecondary() member to check which value was modified. If you need external check, then you may use get_value() and get_secondaryValue() properties of slider. Below is example:

<script type="text/javascript">
function sliderValueChange(slider, evtArgs)
{
 var value = evtArgs.get_newValue();
 var str = 'From evtArgs:<br />' + (evtArgs.get_isSecondary() ? 'Secondary' : 'Main') + ' new value=';
 str += value;
 str += '<br />From slider:<br />main=' + slider.get_value() + '<br />secondary:' + slider.get_secondaryValue();
 $get('span1').innerHTML = str;
}
function showValues()
{
 var slider = $find('<%=WebSlider1.ClientID%>');
 if(!slider)
  return;
 var value1 = slider.get_value();
 var value2 = slider.get_secondaryValue();
 $get('span1').innerHTML = 'Value1:' + value1 + '<br />Value2:' + value2;
}
</script>

   <ig:WebSlider ID="WebSlider1" runat="server" EnableSecondaryValue="true">
     <ClientEvents ValueChanged="sliderValueChange" />
   </ig:WebSlider>
   <input type="button" value="showValues" onclick="showValues()" />
   <br />
   <span id="span1"></span>