var cbxs = document.getElementsByTagName('input'); for (var i in cbxs) { var unique = true; for (var j in listSegIds) { if (listSegIds[j] == cbxs[i].id) { unique = false; } } if (unique && cbxs[i].type == "checkbox" && cbxs[i].id.indexOf("segID") != -1) { count++; listSegIds.push(cbxs[i].id); } }