How to get Dropdown Selected value using javascript in ASP.NET?

HTML

So first add an aspx page into your project & paste the below code for asp:dropdownlist under the form div section:

<asp:DropDownList ID="DropDownList1" runat="server" OnChange="javascript:GetDropDownValue()">

<asp:ListItem Value="1">C#</asp:ListItem>

<asp:ListItem Value="2">ASP</asp:ListItem>

<asp:ListItem Value="3">WPF</asp:ListItem>

<asp:ListItem Value="4">WCF</asp:ListItem>

<asp:ListItem Value="5">C++</asp:ListItem>

asp:DropDownList>

Javascript

Add javascript function in head tag

function GetDropDownValue()

{

var IndexValue = document.getElementById('<%=DropDownList1.ClientID %>').selectedIndex;

var SelectedVal = document.getElementById('<%=DropDownList1.ClientID %>').options[IndexValue].text;

alert(SelectedVal);

}

Output