var _system={
	$:function(id){return document.getElementById(id);},
_client:function(){
  return {w:document.documentElement.scrollWidth,h:document.documentElement.scrollHeight,bw:document.documentElement.clientWidth,bh:document.documentElement.clientHeight};
},
_scroll:function(){
  return {x:document.documentElement.scrollLeft?document.documentElement.scrollLeft:document.body.scrollLeft,y:document.documentElement.scrollTop?document.documentElement.scrollTop:document.body.scrollTop};
},
_cover:function(show){
  if(show){
 this.$("cover").style.display="block";
 this.$("cover").style.width=(this._client().bw>this._client().w?this._client().bw:this._client().w)+"px";
 this.$("cover").style.height=(this._client().bh>this._client().h?this._client().bh:this._client().h)+"px";
}else{
 this.$("cover").style.display="none";
}
},
_guide:function(click){
  this._cover(true);
  this.$("guide").style.display="block";
  this.$("guide").style.top=(_system._scroll().y+5)+"px";
  window.onresize=function(){_system._cover(true);_system.$("guide").style.top=(_system._scroll().y+5)+"px";};
if(click){_system.$("cover").onclick=function(){
	 _system._cover();
	 _system.$("guide").style.display="none";
_system.$("cover").onclick=null;
window.onresize=null;
};}
},
_zero:function(n){
  return n<0?0:n;
}
}