Textbox OnChange

<asp:TextBox ID="actPlanningInside_TextBox" runat="server" TabIndex="7" OnChange="totalActuals()" Width="80px" /> VS is telling me the OnChange call in the above is not valid (although it works). If the above is improper, what is the proper way to do it? All the other code I can find seem to run with a postback whereas the above totals a table using JS.
Thanks
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