How to fire dropdownlist's SelectedIndexChanged without postback?

I'开发者_如何学Gove got a DropDownList on my page databound to a query from my database (Databinding is set up only in my .aspx file, not in codebehind). Next to it I have a second DDL that gets populated from the SelectedIndexChanged function of the first one. This works, but only when AutoPostback is set to true.

Is there a way to fire the SelectedIndexChanged event or manually call this function in my codebehind without having to reload the page every time?

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<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
            Your Stuff with OnSelectedIndexChanged in codebehind
        </ContentTemplate>
    </asp:UpdatePanel>

Rul easy

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I would put the DDLs inside an AJAX UpdatePanel so it only updates that part of the page instead of a full page reload.

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Attach to the <select /> element's onChange event a JavaScript function, and do an AJAX request to a webservice.