var openedMenu = null;
var submenuTimer;

//画像メニューにポインタがきた時
function menuOvr(id){

	// 開いているメニューと違うメニューであれば隠す。
	if (openedMenu && openedMenu != id){
		CloseMenu(id);
	}

	// サブウィンドウの表示
	OpenMenu(id);
}

//レイヤメニューの表示
function OpenMenu(id){ 

	if ( document.getElementById ){
		document.getElementById( id ).style.visibility = 'visible';
	}else if ( document.all ){
		document.all( id ).style.visibility = 'visible';
	}else if ( document.layers ){
		document.layers[ id ].visibility = 'show';
	}

	clearTimeout(submenuTimer);

	openedMenu = id;

}

//レイヤメニューの削除
function CloseMenu(){ 

	if ( document.getElementById ){
		document.getElementById( openedMenu ).style.visibility = 'hidden';
	}else if ( document.all ){
		document.all( openedMenu ).style.visibility = 'hidden';
	}else if ( document.layers ){
		document.layers[ openedMenu ].visibility = 'hide';
	}
	openedMenu = null;
}


//ランダム表示

var iValue, rNumber;
var img1 = new Image();
var img2 = new Image();
var img3 = new Image();
img1 = "common/img/topvisual1.jpg";
img2 = "common/img/topvisual2.jpg";
img3 = "common/img/topvisual3.jpg";	
function display_image(){
	iValue = Math.random() * 3;
	rNumber = Math.ceil(iValue);
	if(rNumber==0) rNumber++;
	document.image1.src=eval("img" + rNumber);
}