function emptySelect( oSelectBox )
{
	for( var i = oSelectBox.options.length -1; i >= 0; i-- )
	{
		oSelectBox.options[i] = null;
	}
}

function toggleVisibility( elCategory )
{
	var iID = elCategory.id.substring( 9 );

	if( $('category_items_'+iID).style.display == 'none' )
	{
		$('img_' + iID).style.backgroundPosition = '0px -11px';
		Effect.BlindDown( $('category_items_'+iID), {duration:0.5} );
	}
	else
	{
		Effect.BlindUp( $('category_items_'+iID), {duration:0.5} );
		$('img_' + iID).style.backgroundPosition = '0px 0px';
	}
}