We need to break apart the one line of code (shown next) and what occurs:
$(<%=ddlMINERAL_ADD.ClientID%>)
The Razor engine things between <% and %> runs on the Server side.
The $() -- jQuery portion -- runs on the client side.
So, where does ddlMINERAL_ADD.ClientID actually have a value? Is it on the client (jquery / javascript side) or does that variable exist on the Server side (in C# code somewhere)?
If it exists in client code then that is why the Razor rendering engine cannot get the value (it runs on the server side before the client code runs).
I had a username that was on the server side, but I needed client-side javascript to have the value. I wrote up how to do that at this StackOverflow:
https://stackoverflow.com/questions/4599169/using-razor-within-javascript/22175868#22175868[
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