/*
Copyright Lutz Eymers <ixtab@polzin.com>, 1997
Polzin GmbH, Duesseldorf
*/

function isDigit( ch )
{
  if ( (ch >= '0') && (ch <= '9') )
    return true;
  else
    return false;
}


function isAlpha( ch )
{
  if ( ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z')) )
    return true;
  else
    return false;
}


function isAlnum( ch )
{
  if ( isAlpha( ch ) || isDigit( ch ) )
    return true;
  else
    return false;
}


function notIn( str1, str2 )
{
  var i = 0;
  var j = str2.length;
  for( ; i<j; i++ )
  {
    var str3 =  str2.charAt(i);
    if( str1.indexOf( str3 ) != -1 )
      return false;
  }
  return true;
}


function checkUsername( username, mustBeQuoted )
{
  var i = 0;
  var j = username.length;
  if ( username.charAt(0) != '"' )
  {
    if ( (username.charAt(0) <  ' ') || (username.charAt(0) >  '~')
          || !notIn( mustBeQuoted, username.charAt(0) ) )
      return false;
    for( i=1; i<j; i++ )
    {
      if ( ( (username.charAt(i) < ' ') || (username.charAt(i) >  '~')
            || !notIn ( mustBeQuoted, username.charAt(i) ) )
           && ( username.charAt(i-1) != '\\' ) )
        return false;
    }
  }
  else
  {
    if ( username.charAt( j-1 ) != '"' )
      return false;
    for( i=1; i<j-1; i++ )
    {
      if ( ( (username.charAt(i) == '\n') || (username.charAt(i) == '\r')
            || (username.charAt(i) == '\"') )
          && (username.charAt(i-1) != '\\') )
        return false;
    }

  }
  return true;
}


function checkNr ( nr )
{
  var i=0;
  var j=nr.length;

  if( j < 1 )
    return false;

  for( ; i<j; i++ )
    if( ( nr.charAt(i) < '0' ) || ( nr.charAt(i) > '9' ) )
      return false;

  return true;
}


function checkIpnr( ipnr )
{
  var iL=0;
  var iC=0;
  var i=0;
  var sNr = "";

  for( ; i< ipnr.length; i++ )
  {
    if ( ipnr.charAt(i) == '.' )
    {
      if ( !iL || (iL> 3) || parseInt( sNr,10 ) > 255 )
        return false;
      iC++;
      iL = 0;
      sNr = "";
      continue;
    }
    if ( isDigit ( ipnr.charAt(i) ) )
    {
      iL++;
      sNr = sNr + ipnr.charAt(i);
      continue;
    }
    return false;
  }

  if ( parseInt( sNr,10 ) > 255 )
    return false;
  if ( ( (iC==3) && (iL>=1) && (iL<=3) ) || ( (iC==4) && (!iL) )  )
    return true;
  else
    return false;
}


function checkFqdn( fqdn )
{
  var iL=0;
  var iC=0;
  var i=fqdn.length-1;

  if ( (fqdn.charAt(0) == '.') || (fqdn.charAt(0) == '-') )
    return false;
  if ( fqdn.charAt(i) == '.' )
    i=i-1;

  for( ; i>=0; i-- )
  {
    if ( fqdn.charAt(i) == '.' )
    {
      if ( iL < 2 && iC < 2 )
        return false;
      if ( fqdn.charAt(i-1) == '-' )
        return false;
      iC++;
      iL = 0;
      continue;
    }
    if ( isAlnum ( fqdn.charAt(i) ) )
    {
      iL++;
      continue;
    }
    if ( fqdn.charAt(i) == '-' )
    {
      if ( !iL )
        return false;
      iL++;
      continue;
    }
    return false;
  }

  if ( !iC || ( iL == 1 && iC < 2 ) || ( !iL && iC==1 ) ) {
    return false;
  }

  return true;

}


function checkHostname( hostname )
{
  if ( hostname.charAt(0) == '[' )
  {
    if ( hostname.charAt(hostname.length-1) != ']' )
      return false;
    var ipnr = hostname.substring( 1, hostname.length -1 );
      return checkIpnr( ipnr );
  }

  if ( hostname.charAt(0) == '#' )
  {
    var nr = hostname.substring( 1, hostname.length );
      return checkNr( nr );
  }

  return checkFqdn( hostname );
}


function checkEmailAdr( address )
{
  var status = true;
  var username = "";
  var hostname = "";

  if ( address.length < 8 )
    return false;

  var seperate = address.lastIndexOf("@");
  if ( seperate == -1 )
    return false;

  username = address.substring(0, seperate );
  if ( ! checkUsername( username, "<>()[],;:@\" " ) )
    return false;

  hostname = address.substring(seperate+1, address.length );
  if ( ! checkHostname( hostname ) )
    return false;

  return true;
}


function checkEmail( email, allowFullname )
{
  var existFullname = false;
  var status = true;
  var fullname = "";
  var adress = "";
  if ( email.length < 8 )
    return false;
  var emailBegin = email.indexOf("<");
  var emailEnd = email.lastIndexOf(">");

  if ( (emailBegin == -1) && (emailEnd == -1) )
    return checkEmailAdr( email );

  if ( ( (emailBegin == -1) && (emailEnd != -1) )
      || ( (emailBegin != -1) && (emailEnd == -1) ) )
    return false;

  adress = email.substring( emailBegin+1, emailEnd );

  if ( ! checkEmailAdr( adress ) )
    return false;

  if ( email.length == adress.length + 2 )
    return true;
  else
    if ( ! allowFullname )
      return false;

  if ( emailEnd == email.length - 1 )
  {
    if ( emailBegin == 0 )
      return true;
    if ( email.charAt( emailBegin -1 ) != ' ' )
      return false;
    fullname = email.substring( 0, emailBegin-1 );
    return checkUsername ( fullname, "<>()[],;:@\"" );
  }

  return false ;

}
/* *********************************************************************** */
function checkForm(form) {

	var warn = "";
	if ( form.email.value == "" ) {
		warn = "Bitte geben Sie ihre E-Mail-Adresse ein!\n";
	} else {
	    if ( js11 ) {
	      if ( ! checkEmail( form.email.value, true ) ) {
	        warn = "Bitte kontrollieren Sie Ihre e-Mail-Adresse!\nEs scheint, als hätte sich ein Fehler eingeschlichen.\n";
	      } else {
	        return true;
	      }
	    }
	}
	
	if ( warn != "" ) {
		alert( "Fehler!\n\n" + warn );
	}
	
	return false;
}