function naviAutoChangeStart() {
	var code = "naviAutoChange('overscene');";
	setTimeout(code, 3000);
}

function naviAutoChange(id) {
	var img = document.getElementById("titleImg");
	var nextId;
	if (img) {
		if (id == "daichimap") {
			img.src = "./seamless/img/title.jpg";
			img.alt = "地球観測衛星だいち（ALOS）が撮影する日本列島高精彩衛星地図。だいちマップ";
			nextId = "overscene";
		}
		else if (id == "overscene") {
			img.src = "./seamless/img/title_ovs.jpg";
			img.alt = "空撮画像をリアルな3次元GIS（3D-GIS）で表現。OverScene";
			nextId = "helitele";
		}
		else if (id == "helitele") {
			img.src = "./helitele/img/title.jpg";
			img.alt = "ヘリコプター映像の撮影位置を瞬時に特定。ヘリテレ撮影位置特定システム";
			nextId = "ucast";
		}
		else if (id == "ucast") {
			img.src = "./ucast/img/title.jpg";
			img.alt = "映像解析により低コストで迅速に交通量を計測。UCast";
			nextId = "daichimap";
		}
	}
	
	var code = "naviAutoChange('" + nextId + "');";
	setTimeout(code, 3000);
}

function naviChange(obj) {
	changeBackgroundImage(obj, "_a.jpg", "_b.jpg");
}

function resetBackgroundImage(obj) {
	changeBackgroundImage(obj, "_b.jpg", "_a.jpg");
}

function changeBackgroundImage(obj, before, after) {
	if (obj && obj.src) {
		var str = "" + obj.src;
		var index = str.indexOf(before, 0);
		obj.src = str.substring(0, index) + after;
	}
}