//スクロールのスピード設定(数値が大にすると高速になる)  
var speed=5;  
  
iens6=document.all||document.getElementById;  
ns4=document.layers;  
  
var crossobj;  
var contentheight;  
  
function pageload() {  
  if (iens6){  
    crossobj=document.getElementById? document.getElementById("content") : document.all.content;  
    contentheight=crossobj.offsetHeight;  
  }  
  else if (ns4){  
    crossobj=document.nscontainer.document.nscontent;  
    contentheight=crossobj.clip.height;  
  }  
  getcontent_height();    
}  
  
function movedown(){  
  if (iens6&&parseInt(crossobj.style.top)>=(contentheight*(-1)+230))  
    crossobj.style.top=parseInt(crossobj.style.top)-speed+"px";  
  else if (ns4&&crossobj.top>=(contentheight*(-1)+230))  
    crossobj.top-=speed;  
  movedownvar=setTimeout("movedown()",20);  
}  
  
function moveup(){  
  if (iens6&&parseInt(crossobj.style.top)<=0)  
    crossobj.style.top=parseInt(crossobj.style.top)+speed+"px";  
  else if (ns4&&crossobj.top<=0)  
    crossobj.top+=speed;  
  moveupvar=setTimeout("moveup()",20)  
}  
  
function getcontent_height(){  
  if (iens6)  
    contentheight=crossobj.offsetHeight;  
  else if (ns4)  
    document.nscontainer.document.nscontent.visibility="show";  
}  
window.onload=pageload;