change value of B1 on condition

[jy2008]

<script>
    $('#calx_form').calx({
        data : {
            B1 : {value: '100'},
            B2 : {value: '200'},
            B3 : {formula: 'B1+B2'},
            B4 : {formula: 'B3^2'}
        }
    });
</script>

for above script, can i revise this script to if I check the checkbox (assume B1 is the cell of a checkbox), B1 value is 10, then if i uncheck the checkbox, then B1 value is 20?