Get selected index, value,text of ASP.Net drop down list in javascript

<%-- In Head section--%>
  <script type="text/javascript" language="javascript">
   
            function getDropdownListValues() {
            var DropdownList = document.getElementById('<%=aspdropdown.ClientID %>');
            var SelectedIndex = DropdownList.selectedIndex;
            var SelectedValue = DropdownList.value;
            var SelectedText = DropdownList.options[DropdownList.selectedIndex].text;

            var LabelDropdownList = document.getElementById('<%=lblDropdownList.ClientID %>');
            var sValue = 'Index: ' + SelectedIndex + '<br/> Selected Value: ' + SelectedValue + '<br/> Selected Text: ' + SelectedText;

            LabelDropdownList.innerHTML = sValue;
        }
    </script>






<%-- In body section--%>
 


 <div>
        <asp:Label runat="server" ID="lblText">Asp.net DropdownList</asp:Label><br />
  
        <asp:DropDownList ID="aspdropdown" runat="server" onchange="getDropdownListValues();">
            <asp:ListItem Value="Test1" Text="Testing1"></asp:ListItem>
            <asp:ListItem Value="Test2" Text="Testing2"></asp:ListItem>
            <asp:ListItem Value="Test3" Text="Testing3"></asp:ListItem>
            <asp:ListItem Value="Test4" Text="Testing4"></asp:ListItem>
            <asp:ListItem Value="Test5" Text="Testing5"></asp:ListItem>
        </asp:DropDownList> <br />
  
        <asp:Label runat="server" ID="lblDropdownList"></asp:Label>
    </div>