Calling javascript with ClientID

I have an asp text box that sits within a gridview. I would like to call a javascript method OnBlur and pass the ClientID of the textbox to the javascript method. How to do. Below is my markup. Any help would be much appreciated. Code below does not seem to work.

<asp:TextBox ID="txtInsertUnitRCVEmpty" TabIndex="81"  OnBlur="javascript:checkforvalidation('<%= txtInsertUnitRCVEmpty.ClientID %>');" onkeydown="return isNumber(event);"   Width="100px" runat="Server" Text="0.00"></asp:TextBox>


Jason