function get_base()
{
	var scripts = document.getElementsByTagName( "script" );
	for( var i = 0; i < scripts.length; ++i )
	{
		var row = scripts[ i ].src;
		var n = row.indexOf( "js/jnatools.js" );
		if( n >= 0 )
			return( row.slice( 0, n ) );
	}

	return( "" );
}