var i = 5   //アニメーションの移動距離
var j = 5
var speed = 60  //アニメーションの移動速度
var img_w = 20  //画像のゆとり（画像が隠れてしまうのを防ぐため。）
var img_h = 20
var ox_obj,W,H
var ox_obj_top,ox_obj_left

var ms = navigator.appVersion.indexOf("MSIE");
var ie4 = (ms>0) && (parseInt(navigator.appVersion.substring(ms+5, ms+6)) >= 4)
var nesc = navigator.appName.lastIndexOf("Netscape"); //一致した位置(0)を返す
var nesc4 = (nesc >= 0) && (parseInt(navigator.appVersion.substring(0,2)) >= 4);

function fly(){

	if(ie4 || nesc4){
		if(document.layers){
			W = window.innerWidth
			H = window.innerHeight
			ox_obj = eval("document.ox")
			ox_obj.top = ox_obj.top + i
			ox_obj.left = ox_obj.left + j
			ox_obj_top = ox_obj.top
			ox_obj_left = ox_obj.left
		}else {
			W = document.body.clientWidth
			H = document.body.clientHeight
			ox_obj = eval("ox.style")
			ox_obj.posTop = ox_obj.posTop + i
			ox_obj.posLeft = ox_obj.posLeft + j 

			ox_obj_top = ox_obj.posTop
			ox_obj_left = ox_obj.posLeft
		}

	if(ox_obj_top >= (H - img_h)) i = -5
	if(ox_obj_left >= (W - img_w)) j= -5
	if(ox_obj_top <= 0) i = 5
	if(ox_obj_left <= 0) j = 5
	setTimeout("fly()", speed)
	}

}