a

 var fields = new Array(); fields[0] = 'f1'; fields[1] = 'f2'; fields[2] = 'f3'; var result = new Array(); var len = fields.length; for (var i=0; i < len; i++) {      if (document.getElementById(fields[i]).checked) {          result[fields[i]] = true;      } else {          result[fields[i]] = false;      } }