$('email').addEvent('change',function() {
  if(!$('email').getProperty('value').test('@')) alert('Please check your email address');
});
$('phone').addEvent('keyup',function() {
  var validChars = '1234567890-extXT ';
  var phonenum = $('phone').getProperty('value');
  var cleanone = '';
  for(i=0; i<phonenum.length; i++) { 
    var c = phonenum.charAt(i);
    if (validChars.indexOf(c) !== -1) cleanone += c;
  };
  $('phone').setProperty('value',cleanone);
});