function CallBack_book(xmlhttp)
{
    result1 = xmlhttp.responseText;
    $("all_book").innerHTML=result1;
	xmlhttp=null;
	result1=null;
	CollectGarbage();
}
function CallAjax_book(typeid,to_page) {
	var rel="t_type="+typeid+"&to_page="+to_page;
	var url='book_list.php';
	var myAjax = new Ajax.Request(url,{parameters: rel,onSuccess: CallBack_book});
} 
function booktype(typename){
$("whichtype").innerHTML="  当前书籍类别："+typename;
}