请问"顶一下"的PHP代码?

<a href="#" id='name'onclick="refresh();">顶一下<div id='show'><?=$time?></div></a>
js.js

var XMLHttp;
function createXMLHttpRequest(){
if(window.XMLHttpRequest){
XMLHttp = new XMLHttpRequest();
}
else if(window.ActiveXObject){
try{
XMLHttp = new ActiveX0bject("Msxml2.XMLHTTP");
}catch(e){}
try{
XMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
}catch(e){}
if(!XMLHttp){
window.alert("不能创建XMLHttpRequest对象实例");
return false;
}
}
}
function refresh() {
createXMLHttpRequest();

var url = "refresh.php";
XMLHttp.open("GET",url, true);
XMLHttp.onreadystatechange = login;
XMLHttp.send(null);
}