function over(id,pre,num )
{
	for(var i=1;i<=num;i++)
	{
		var obj1=document.getElementById(pre+i);
		var obj2=document.getElementById(pre+i+"_content");
		if(i==id)
		{
			obj1.className="m_on";
			obj2.className="content";
		}
		else
		{
			
							obj1.className="m_off";
							obj2.className="content_off";
						
		  }
	}
}

function switchClass(sid){
	
	  var j = document.getElementById("subclass_"+sid);
	  var img = document.getElementById("img_"+sid);
	   var type;
	   if(img.src.indexOf("add.gif") != -1){
	   	type = "add";
	   }
	   if(type == 'add' ){
	   	j.style.display = "block";
		img.src = "/book/images/remus.gif";
		img.title = "点击这里可以隐藏下级分类";
	   }else{
	   	j.style.display = "none";
		img.src = "/book/images/add.gif";
		img.title = "点击这里可以展开下级分类";
	   }
	  
}