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>