var isNN = ( navigator.appName.indexOf( "Netscape" ) != -1 );

function autoTab( input, len, e ) 
{

  var keyCode = ( isNN ) ? e.which : e.keyCode; 
  var filter = ( isNN ) ? [ 0, 8, 9 ] : [ 0, 8, 9, 16, 17, 18, 37, 38, 39, 40, 46 ];

  if( input.value.length >= len && !containsElement( filter,keyCode ) ) 
  {
  
      input.value = input.value.slice( 0, len );
      input.form[ ( getIndex( input ) + 1 ) % input.form.length ].focus();

  }

  function containsElement( arr, ele ) 
  {

    var found = false, 
        index = 0;
    
    while( !found && index < arr.length )
    
    if( arr[ index ] == ele )
      found = true;
    else
      index++;
      
    return found;

  }

  function getIndex( input ) 
  {

    var index = -1, 
        i = 0, 
        found = false;
        
    while( i < input.form.length && index == -1 )
      if( input.form[ i ] == input )
        index = i;
      else i++;
        return index;
        
  }
  
  return true;

}

function noenter( e ) 
{

  // IE 
  if( window.event )
  {
    
    if( window.event.keyCode == 13 )
    {
      
      window.event.cancelBubble = true;
      window.event.returnValue = false;
      
    }
    
    return;
    
  }
  
  // Netscape/Mozilla/FireFox
  if( e.which )
  {
    
    return e.which != 13;
    
  }
  
}