Check checkbox before clicking button

<input id="chkTermsAndCondition" type="checkbox" /><br/><br/>
<asp:Button ID="btnCheckOut1" runat="server" Text="COMPLETE ORDER"  OnClientClick="return CheckTerms();"/>

<script type="text/javascript">
        function CheckTerms() {            
            if ($('#chkTermsAndCondition').is(':checked')) {
                return true;
            }
            else {
                alert("Please accept the terms and conditions !");
                return false;
            }
        }
    </script>