how to pass textbox value to checkbox on checkbox click in jquery

<script type="text/javascript">
        $(function () {
            $(".chb").click(function () {
                if (this.checked) {
                    var txtVal = $("#txt").val();
                    $(this).val(txtVal);
                }
            });
        });
</script>

<input type="text" id="txt" /><br />
<input type="checkbox" class="chb" value="10" />A<br />
<input type="checkbox" class="chb" value="20" />B<br />
<input type="checkbox" class="chb" value="30" />C<br />
<input type="checkbox" class="chb" value="40" />D<br />
<input type="checkbox" class="chb" value="50" />E<br />