// check email address
	function checkMail( MailAddress )
	{
		reg = new RegExp('^([a-zA-Z0-9\\-\\.\\_]+)(\\@)([a-zA-Z0-9\\-\\.]+)(\\.)([a-zA-Z]{2,4})$');
		if( reg.test( MailAddress ) )
			return true;
		else
		{
			return false;
		}
	}

	// this function loads a guestbook page
	function loadGuestbookPage( Page )
	{
		$( 'content-div' ).hide();
		$( 'entry-loading-div' ).show();

		new Ajax.Updater( 'content-div', 'get_entries.php',
					{
						onSuccess: function( transport )
						{
							$( 'entry-loading-div' ).hide();
							$( 'content-div' ).show();
						},
						onFailure: function( transport )
						{
							//alert( 'Error: ' + transport.status + "\nstatus: " + transport.statusText + "\ndomain: " + document.domain + "\nurl: " + document.URL);
						},
						parameters: { page: Page }
					}
					);
	}
	
	// this function checks the submit form and sends it to the server if appropiate
	function submitInputForm()
	{

		var Error = false;

		$( 'name-error' ).hide();
		$( 'e-mail-error' ).hide();
		$( 'entry-error' ).hide();

		if( $F( 'name' ) == "" )
		{
			$( 'name-error' ).show();
			Error = true;
		}
		if( !checkMail( $F( 'e-mail' ) ) )
		{
			$( 'e-mail-error' ).show();
			Error = true;
		}
		if( $F( 'entry' ) == "" )
		{
			$( 'entry-error' ).show();
			Error = true;
		}
		
		if( !Error )
		{
			$( 'input-div' ).hide();
			$( 'input-submitting' ).show();
			new Ajax.Updater( 'submit-result', 'add_entry.php',
							{
								onSuccess: function(transport){
																$( 'input-submitting' ).hide();
																$( 'submit-result' ).show();
																loadGuestbookPage( 0 );
															  },
								parameters: { name: $F( 'name' ), email: $F( 'e-mail' ), entry: $F( 'entry' ) } } );
		}
		
		return false;
	}

	// load content when page loaded
	window.onload = function()
	{
		$( 'input-div' ).show();
		loadGuestbookPage( 0 );
	}