var speed = 100
var ox_obj,W,H
var x,y
var dir = 0.0
var vx = 100.
var vy = 2.9
var dt = -0.1
var g = -5.9
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"); 
var nesc4 = (nesc >= 0) && (parseInt(navigator.appVersion.substring(0,2)) >= 4)
function ugoku(){
  if(document.layers){
    x=30.,y=window.innerHeight * 0.7
  }else{
    x=30.,y=document.body.clientHeight * 0.7
  }
  setTimeout('fly()', 100)
}
function fly(){
  if(ie4 || nesc4){
    if(document.layers){
      W = window.innerWidth
      H = window.innerHeight
      vy += g*dt
      y += vy*dt
      x += vx*dt
      ox_obj = eval("document.ox")
      ox_obj.top = H * 0.87 - y
      ox_obj.left = x
    }else{
      W = document.body.clientWidth
      H = document.body.clientHeight
      vy += g*dt
      y += vy*dt
      x += vx*dt
      ox_obj = eval("ox.style")
      ox_obj.posTop = H * 0.87 - y
      ox_obj.posLeft = x
    }
    if (x > W * 0.87) {vx = -vx}
    if (x < -20){vx = -vx}
    if (y <= 0.) {vy = -vy;y=-y}
    //t = t + dt;
    setTimeout("fly()", speed)
  }
}