function get_maker()
{
	var node = new Array();
	var exist;

	for( var i = 0; i < arr_cars.length; i++ )
	{
		exist = false;
		str = arr_cars[i].split( "|" );

		for ( var j = 0; j < node.length; j++ )
		{
			if ( node[j] == str[0] )
			{
				exist = true;
				break;
			}
		}

		if ( !exist )
		{
			node[node.length] = str[0];
		}
	}
	return node.sort();
}

function get_model( maker )
{
	var node = new Array();
	var exist;

	for( var i = 0; i < arr_cars.length; i++ )
	{
		exist = false;
		str = arr_cars[i].split( "|" );

		if ( maker == str[0] )
		{
			for ( var j = 0; j < node.length; j++ )
			{
				if ( node[j] == str[1] )
				{
					exist = true;
					break;
				}
			}

			if ( !exist )
			{
				node[node.length] = str[1];
			}
		}
	}
	return node.sort();
}

function get_grade( maker, model )
{
	var node = new Array();
	var exist;
	for( var i = 0; i < arr_cars.length; i++ )
	{
		exist = false;
		str = arr_cars[i].split( "|" );

		if ( maker == str[0] && model == str[1] && str[2] != "" )
		{
			for ( var j = 0; j < node.length; j++ )
			{
				if ( node[j] == str[2] )
				{
					exist = true;
					break;
				}
			}

			if ( !exist )
			{
				node[node.length] = str[2];
			}
		}
	}
	return node.sort();
}

function sel_maker( frm, val, maker_str )
{
	sel_reset( frm.maker, "** ¸ÞÀÌÄ¿ **" );
	var maker = get_maker( maker_str );
	for( var i = 0; i < maker.length; i++ )
	{
		frm.maker.options[i + 1] = new Option( maker[i], maker[i] );
		if( val == maker[i] ) 
			frm.maker.selectedIndex = i + 1;
	}
	sel_reset( frm.model, "** ¸ðµ¨ **" );
	sel_reset( frm.grade, "** ±×·¹À̵å **" );
}

function sel_model( frm, val, model_str )
{
	sel_reset( frm.model, "** ¸ðµ¨ **" );
	var maker = frm.maker.value;
	var model = get_model( maker, model_str );
	for( var i = 0; i < model.length; i++ )
	{
		frm.model.options[i + 1] = new Option( model[i], model[i] );
		if( val == model[i] ) 
			frm.model.selectedIndex = i + 1;
	}
	sel_reset( frm.grade, "** ±×·¹À̵å **" );
}

function sel_grade( frm, val, grade_str )
{
	sel_reset( frm.grade, "** ±×·¹À̵å **" );
	var maker = frm.maker.value;
	var model = frm.model.value;
	var grade = get_grade( maker, model, grade_str );
	for( var i = 0; i < grade.length; i++ )
	{
		frm.grade.options[i + 1] = new Option( grade[i], grade[i] );
		if( val == grade[i] ) 
			frm.grade.selectedIndex = i + 1;
	}
}

function sel_reset( obj, val )
{
	for( var i = obj.length; i > -1; i-- ){
		obj.options[i] = null;
	}
	obj.options[0] = new Option( val, "" );
	obj.selectedIndex = 0;
}