DEDECMS でキーボードを使用してページを上下に移動する方法

$this->PreNext[&#39;pre&#39;] = "上一篇：<a href=&#39;$mlink&#39;>{$preRow[&#39;title&#39;]}</a> ";

$this->PreNext['pre'] = "$mlink ";
$this->PreNext[&#39;next&#39;] = "下一篇：<a href=&#39;$mlink&#39;>{$nextRow[&#39;title&#39;]}</a> ";

<script type="text/javascript" language="javascript">
<!--
document.onkeydown=nextpage;
var prevpage=&#39;{dede:prenext get=&#39;pre&#39;/}&#39;;
var nextpage=&#39;{dede:prenext get=&#39;next&#39;/}&#39;;
var index_page = "index.html";
//var bookpage="index.html";
function nextpage(event)
{
event = event ? event : (window.event ? window.event : null);
//if (event.keyCode==13) location=bookpage
if (event.keyCode==13) location=index_page
if (event.keyCode==37)
{
if (prevpage!=&#39;&#39; && prevpage!=&#39;上一篇：没有了 &#39;)
location=prevpage;
else
alert(&#39;这是第一页&#39;);
}
if (event.keyCode==39)
{
if (nextpage!=&#39;&#39; && nextpage!=&#39;下一篇：没有了 &#39;)
location=nextpage;
else
alert(&#39;已经是最后一页了&#39;);
}
}
//-->
function getElement(aID)
{
return (document.getElementById) ? document.getElementById(aID): document.all[aID];
}
function makeRequest(url){
http_request=false;
if(window.XMLHttpRequest){//Mozilla,Safari,...
http_request=new XMLHttpRequest();
if(http_request.overrideMimeType){
http_request.overrideMimeType(&#39;text/xml&#39;);
}
}else if(window.ActiveXObject){//IE
try{
http_request=new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
http_request=new ActiveXObject("Microsoft.XMLHTTP");
}catch(e){}
}
}
if(!http_request){
alert(&#39;Giving up:(Cannot create an XMLHTTP instance)&#39;);
return false;
}
return http_request;
}
</script>