var scrolling;

var step = 10;
var delay = ( navigator.appName == "Microsoft Internet Explorer" ) ? 10 : 1;
var scroll_width = 110;

function scroll_right()
{
	if ( !scrolling )
	{
		scrolling = window.setInterval( 'scroll( -' + step + ' )', delay );
	}
}

function scroll_left()
{
	if ( !scrolling )
	{
		scrolling = window.setInterval( 'scroll( +' + step + ' )', delay );
	}
}

function scroll( increment )
{
	var left = parseInt( document.getElementById( 'content' ).style.left ) + parseInt( increment );
	var right = parseInt( document.getElementById( 'window' ).style.width );

	document.getElementById( 'content' ).style.left = left + "px";

	if ( ( left % scroll_width ) == 0 )
	{
		var width = parseInt( document.getElementById( 'content' ).style.width );

		document.getElementById( 'left_arrow'  ).style.visibility = ( left         < 0     ) ? "visible" : "hidden";
		document.getElementById( 'right_arrow' ).style.visibility = ( left + width > right ) ? "visible" : "hidden";

		window.clearInterval( scrolling );

		scrolling = false;
	}
}