$(document).ready(function() {
    /* ensure all checked rows are highlighted */
    $('.factors-form li:has(:checkbox:checked)').addClass('checked');
    /* add click event handlers to all checkboxes */
    $('.factors-form li :checkbox').click(function() {
        $(this).parent().toggleClass('checked');
        return true;
    });
    /* mark all options with modifiers */
    $('.factors-form li:has(p)').addClass('has-modifiers');
});