HTML:
1 <asp:DropDownList ID="DropdownList1" runat="server" AutoPostBack="true" />
JS:
1 <script type="text/JavaScript"> 2 function getvalue(){ 3 4 var select1 = document.all.<%= DropdownList1.ClientID %>; 5 var selectvalue = select1.options[select1.selectedIndex].value; 6 var selectText= select1.options[select1.selectedIndex].text; 7 alert(selectvalue+" "+selectText); 8 } 9 </script>