<asp:CheckBox ID="ckbTable" runat="server" Checked="false" />

<table id="table" style="display:none" border="0" cellspacing="0" cellpadding="0" >

<tr>

<td>123</td>

</tr>

</table>

$(function(){

$("#ckbTable").click(function () {

                if (this.checked) {

                    $("#table").css("display", "block");

                }

                else {

                    $("#table").css("display", "none");

                }

            });

});