In this article I will explain with an example, how to use implement OnChange using jQuery in ASP.Net DropDownList.
 
 

HTML Markup

The following HTML Markup consists of: DropDownList with some items.
<asp:DropDownList ID="ddlFruits" runat="server">
    <asp:ListItem Text="Please select" Value=""></asp:ListItem>
    <asp:ListItem Text="Mango" Value="1"></asp:ListItem>
    <asp:ListItem Text="Apple" Value="2"></asp:ListItem>
    <asp:ListItem Text="Banana" Value="3"></asp:ListItem>
</asp:DropDownList>
 
 

Client Side OnChange event jQuery implementation

First, the following script file is inherited.
1. jquery.min.js
Then, inside the document.ready event handler, the DropDownList has been assigned with an jQuery change event handler.
When an item is selected in the DropDownList, the Text and Value part of the selected Item are fetched and displayed in JavaScript Alert Message Box.
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $("[id*= ddlFruits]").change(function () {
            var selectedText = $(this).find("option:selected").text();
            var selectedValue = $(this).val();
            alert("Selected Text: " + selectedText + " Value: " + selectedValue);
        });
    });
</script>
 
 

Screenshot

ASP.Net DropDownList: Client Side OnChange event in jQuery
 
 

Demo

 
 

Downloads