php+ajax无刷新分页实例详解

<meta 'Content:text/html;charset=utf-8'></meta>
<title>ajax分页演示</title>
<script language="javascript" src="js/ajaxpage.js"></script>
<div id="result">
<?php
$db=mysql_connect("localhost","root","123456");
mysql_select_db("register");
mysql_query("set names 'utf-8'");
$result=mysql_query("select * from user");
$total=mysql_num_rows($result) or die(mysql_error());
$page=isset($_GET['page'])?intval($_GET['page']):1;
$page_size=5;
$url='ajax_page_show_userinfo.php';
$pagenum=ceil($total/$page_size);
$page=min($pagenum,$page);
$prepage=$page-1;
$nextpage=($page==$pagenum?0:$page+1);
$pageset=($page-1)*$page_size;
$pagenav.="显示第".($total?($pageset+1):0)."-".min($pageset+5,$total)."记录 共<b>".$total."</b>条记录 现在是第 <b>".$page."</b> 页 ";
if($page<=1)
$pagenav.="<a style=cursor:not-allowed;>首页</a> ";
else
$pagenav.="<a onclick=javascript:dopage('result','$url?page=1') style=cursor:pointer;>首页</a> ";
if($prepage)
$pagenav.="<a onclick=javascript:dopage('result','$url?page=$prepage') style=cursor:pointer;>上一页</a> ";
else
$pagenav.="<a style=cursor:not-allowed;>上一页</a> ";
if($nextpage)
$pagenav.="<a onclick=javascript:dopage('result','$url?page=$nextpage') style=cursor:pointer;>下一页</a> ";
else
$pagenav.="<a style=cursor:not-allowed;>下一页</a> ";
if($pagenum)
$pagenav.="<a onclick=javascript:dopage('result','$url?page=$pagenum') style=cursor:pointer;>尾页</a> ";
else
$pagenav.="<a style=cursor:not-allowed;>尾页</a> ";
$pagenav.="共".$pagenum."页";
if($page>$pagenum){
  echo "error:没有此页".$page;
  exit();
}
?>
<table align="center" border="2" width="300">
 <tr bgcolor="#cccccc" align="center">
  <td>用户名</td>
  <td>用户密码</td>
 </tr>
<?php
$info=mysql_query("select * from user limit $pageset,$page_size");
while($array=mysql_fetch_array($info)){
?>
 <tr align="center">
  <td><?php echo $array['username'];?></td>
  <td><?php echo $array['password'];?></td>
 </tr>
<?php  
}
?>
</table>
<?php
echo "<p align=center>$pagenav</p>";
?>
</div>

var http_request=false;
function send_request(url){//初始化，指定处理函数，发送请求的函数
  http_request=false;
 //开始初始化XMLHttpRequest对象
 if(window.XMLHttpRequest){//Mozilla浏览器
 http_request=new XMLHttpRequest();
 if(http_request.overrideMimeType){//设置MIME类别
  http_request.overrideMimeType("text/xml");
 }
 }
 else if(window.ActiveXObject){//IE浏览器
 try{
  http_request=new ActiveXObject("Msxml2.XMLHttp");
 }catch(e){
  try{
  http_request=new ActiveXobject("Microsoft.XMLHttp");
  }catch(e){}
 }
  }
 if(!http_request){//异常，创建对象实例失败
 window.alert("创建XMLHttp对象失败！");
 return false;
 }
 http_request.onreadystatechange=processrequest;
 //确定发送请求方式，URL，及是否同步执行下段代码
 http_request.open("GET",url,true);
 http_request.send(null);
}
//处理返回信息的函数
function processrequest(){
  if(http_request.readyState==4){//判断对象状态
   if(http_request.status==200){//信息已成功返回，开始处理信息
  document.getElementByIdx(reobj).innerHTML=http_request.responseText;
 }
 else{//页面不正常
  alert("您所请求的页面不正常！");
 }
  }
}
function dopage(obj,url){
  //document.getElementByIdx(obj).innerHTML="正在读取数据...";
  send_request(url);
  reobj=obj;
}