var ImageMsgDatas = new Array;
var ImageDatas = new Object();
var BrowserVers = parseInt( navigator.userAgent.charAt( navigator.userAgent.indexOf( "/" )+1 ), 10 );

function IsIE() { return navigator.userAgent.indexOf( "MSIE" ) > 0; }

function InitImageSwap( name, img1, img2, msg )
{
	ImageDatas[name] = new Object();
	ImageDatas[name][0] = new Image();
	ImageDatas[name][0].src = img1;
	ImageDatas[name][1] = new Image();
	ImageDatas[name][1].src = img2;
	ImageMsgDatas[name] = msg;
}

function FindElement( n )
{
	if ( BrowserVers < 4 ) {
		return document[n];
	}

	var e = document[n];
	if ( !e ) {
		for ( var i = 0; i < document.layers.length; i++ ) {
			e = FindElement( n, document.layers[i] );
			if ( e ) { return e; }
		}
	}
	return e;
}

function ExecImageSwap( name, index )
{
	if ( document.images ) {
		if ( ImageDatas[name] ) {
			var img = !IsIE()? FindElement( name, 0 ): document[name];

			if ( img && typeof( ImageDatas[name][index].src ) != "undefined" ) {
				img.src = ImageDatas[name][index].src;
			}
			if ( index != 0 && ImageMsgDatas[name] != "" ) {
				self.status = ImageMsgDatas[name];
			} else {
				self.status = " ";
			}
			return true;
		}
	}
	return false;
}

function ButtonReturn()
{
	if ( navigator.appName.indexOf("Explorer") >= 0 && navigator.userAgent.indexOf("Mozilla/3") >= 0 && navigator.userAgent.indexOf("Mac") >= 0 ) {
		return false;
	} else {
		return true;
	}
}

InitImageSwap( '_BUTTON0', 'images/back.gif', 'images/back3.gif', 'トップへ戻る' );