function invertSelections() { 'use strict'; var form = document.getElementById('choose_pages' ), num_elements = form.elements.length, i, cur_element; for (i = 0; i < num_elements; i++) { cur_element = form.elements[i]; if (cur_element.type === "checkbox" && cur_element.id !== 'create-redirect' && cur_element.id !== 'watch-pages') { form.elements[i].checked = form.elements[i].checked !== true; } } }