var top=0;
var last_top=0;
var Swi = 0;
var default_height=0;
if(navigator.appVersion.indexOf('Safari') != -1){
  var target_suffix = '';
}else{
  var target_suffix = '.px';
}
function item_set(){
  item_layer();
}
function item_layer(){
  var now_top;
  var now_left;
  if(window.pageYOffset){
    now_top = window.pageYOffset;
  }else if(document.body.scrollTop){
    now_top = document.body.scrollTop;
  }else if(document.body.parentNode.scrollTop){
    now_top = document.body.parentNode.scrollTop;
  }else if(window.scrollY){
    now_top = window.scrollY;
  }else{
    now_top = 0;
  }
  ppp = document.getElementById('Item').style.top;
  ooo = ppp.replace(/px/,"");
  if(now_top > 220){
    if(navigator.platform == 'MacPPC' && navigator.appName.charAt(0) == "M"){
      num = 220;
    }else{
      num = 220;
    }
    document.getElementById('Item').style.top= now_top - num + target_suffix;
  }else if(now_top > ooo){
  }else{
    document.getElementById('Item').style.top= now_top  + target_suffix;
  }
  if(navigator.platform == 'MacPPC' && navigator.appName.charAt(0) == "M"){
    document.getElementById('Maintable').style.visibility =  "hidden";
    document.getElementById('Maintable').style.zIndex =  2;
    document.getElementById('Maintable').style.visibility =  "visible";
    setTimeout('item_layer()', 500);
  }else{
    setTimeout('item_layer()', 20);
  }

}