How do I select my asp.net dropdownlist in jquery?

Hello everyone I usually can select my asp.net control using this method:
$("#<%= txtTest.ClientID %>").datepicker({ dateFormat: 'dd/mm/yy' }); However, I have this code and it doesnt work. Not sure why:
var test = $("#<%= ddlTest.ClientID %> option:selected").text(); <asp:DropDownList ID="ddlTest" runat="server" DataTextField="test_name" DataValueField="test_id"></asp:DropDownList> It keeps throwing syntax error. Unrecoginzed expression. How do I select this? Thanks