String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ''); };

function validateEmail(addr) {
  if (addr.trim() == '') {
     return 'Email Address is required.';     
  }

  var invalidChars = '\/\'\\ ";:?!()[]\{\}^|';
  for (i=0; i<invalidChars.length; i++) {
     if (addr.indexOf(invalidChars.charAt(i),0) > -1) {
        return 'Email Address contains invalid characters';
     }
  }
  for (i=0; i<addr.length; i++) {
     if (addr.charCodeAt(i)>127) {
        return "Email Address contains non ascii characters.";
     }
  }
  
  var atPos = addr.indexOf('@',0);
  
  if (atPos == -1) {
     return 'Email Address must contain an @';
  }
  if (atPos == 0) {
     return 'Email Address must not start with @';
  }
  if (addr.indexOf('@', atPos + 1) > - 1) {
     return 'Email Address must contain only one @';
  }
  if (addr.indexOf('.', atPos) == -1) {
     return 'Email Address must contain a period in the domain name';
  }
  if (addr.indexOf('@.',0) != -1) {
     return 'period must not immediately follow @ in Email Address';
  }
  if (addr.indexOf('.@',0) != -1){
     return 'period must not immediately precede @ in Email Address';
  }
  if (addr.indexOf('..',0) != -1) {
     return 'two periods must not be adjacent in Email Address';
  }
  var suffix = addr.substring(addr.lastIndexOf('.')+1);
  if (suffix.length != 2 && suffix != 'com' && suffix != 'net' && suffix != 'org' && suffix != 'edu' && suffix != 'int' && suffix != 'mil' && suffix != 'gov' & suffix != 'arpa' && suffix != 'biz' && suffix != 'aero' && suffix != 'name' && suffix != 'coop' && suffix != 'info' && suffix != 'pro' && suffix != 'museum') {
     return 'invalid primary domain in Email Address';
  }
  return '';
}