function addBookmark( id)
	{ 
		$('#add-bookmark-'+id).hide(); 
		$('#remove-bookmark-'+id).show(); 
		$.ajax({
			url: '/bookmark/ajax',
			data: {oper:'add', 'id': id},
			type: 'post'
		});
		$('#bookmarkButton').fadeIn();
	} 
	function removeBookmark( id)
	{ 
		$('#remove-bookmark-'+id).hide(); 
		$('#add-bookmark-'+id).show(); 
		$.ajax({
			url: '/bookmark/ajax',
			data: {oper:'del', 'id': id},
			type: 'post'
		});
	} 
	// removes whole entry from the list (instead of switching buttons)
	function removeBookmark2( id)
	{
		$( '#wohnung-'+id).remove(); 
		$.ajax({
			url: '/bookmark/ajax',
			data: {oper:'del', 'id': id},
			type: 'post'
		});
	}