function isValidEmail (s) {
 var a = false;
 var res = false;
 if(typeof(RegExp) == 'function') {
  var b = new RegExp('abc');
  if(b.test('abc') == true){a = true;}
 }
 if(a == true) {
  reg = new RegExp('^([a-zA-Z0-9\\-\\.\\_]+)'+
                   '(\\@)([a-zA-Z0-9\\-\\.]+)'+
                   '(\\.)([a-zA-Z]{2,4})|(museum)$');
  res = (reg.test(s));
 } else  {
  res = (s.search('@') >= 1 &&
         s.lastIndexOf('.') > s.search('@') &&
         s.lastIndexOf('.') >= s.length-5)
 }
 return(res);
}