php 实用例子：购物车 涉及session与ajax

login：

<div>用户名：<input type="text" id="uid" /></div>
<div>密码：<input type="text" id="pwd" /></div>
<input type="button" value="登录" id="btn" />
</body>
<script type="text/javascript">
$("#btn").click(function(){
 var uid = $("#uid").val();
 var pwd = $("#pwd").val();
 
 $.ajax({
   url:"loginchuli.php",
   data:{u:uid,p:pwd},
   type:"POST",
   dataType:"TEXT",
   success: function(data){
    if(data.trim()=="OK")
    {
     window.location.href="main.php";
    }
    else
    {
     alert("用户名或密码错误");
    }
    }
  });
 
 })
</script>

loginchuli：

<?php
session_start();
include("../DBDA.class.php");
$db = new DBDA();

$uid = $_POST["u"];
$pwd = $_POST["p"];

$sql = "select password from login where username='{$uid}'";

$mm = $db->StrQuery($sql);

if($mm==$pwd && $pwd!="")
{
 $_SESSION["uid"]=$uid;
 echo "OK";
}
else
{
 echo "NO";
}

main：

<?php
session_start();
include("../DBDA.class.php");
$db = new DBDA();
?>

<style type="text/css">
.list{ width:100%; height:30px; margin-top:10px; text-align:center; line-height:30px; vertical-align:middle}
</style>

<div style="width:100%; height:100px;
 <h1 style="float:left">大苹果商城</h1>
    <a style="float:right; margin-top:40px" href="zhuxiao.php">注销</a>
</div>
<br />
<div style="width:100%; height:600px">
 <div id="left" style="width:20%; float:left">
     <a href="main.php"><div class="list">浏览商品</div></a>
        <a href="zhanghu.php"><div class="list">查看账户</div></a>
        <a href="gouwuche.php"><div class="list">查看购物车</div></a>
    </div>
   
 <div id="right" style="width:80%; float:left">
   
    <?php
 $agwc = array();
 if(!empty($_SESSION["gwc"]))
 {
  $agwc = $_SESSION["gwc"];
 }
 $zhonglei = count($agwc);
 $sum = 0;
 foreach($agwc as $v)
 {
  $sql = "select price from fruit where ids='{$v[0]}'";
  $danjia = $db->StrQuery($sql);
  $sum = $sum +$danjia*$v[1];
 }
 echo "<div>购物车中有:{$zhonglei}种商品，总价格为:{$sum}元.</div>";
 ?>
   
     <table width="100%" border="1" cellpadding="0" cellspacing="0">
        <tr>
         <td>代号</td>
            <td>水果名称</td>
            <td>水果价格</td>
            <td>源产地</td>
            <td>库存量</td>
            <td>操作</td>
        </tr>
       
        <?php
 
  
  $sql = "select * from fruit";
  $attr = $db->Query($sql);
  
  foreach($attr as $v)
  {
   echo "<tr><td>{$v[0]}</td>
            <td>{$v[1]}</td>
            <td>{$v[2]}</td>
            <td>{$v[3]}</td>
            <td>{$v[4]}</td>
            <td><a href='goumai.php?code={$v[0]}'>购买</a></td></tr>";
  }
  ?>
       
        </table>
    </div>
</div>

goumai：

<?php
session_start();
$code = $_GET["code"];

if(empty($_SESSION["gwc"]))
{
 //第一次点击购买
 $attr = array(
  array($code,1)
 );
 $_SESSION["gwc"] = $attr;
}
else
{
 //不是第一次点击购买
 $attr = $_SESSION["gwc"];
 $bs=0;
 foreach($attr as $k=>$v)
 {
  if($v[0]==$code)
  {
   $bs=1;
   $attr[$k][1] = $attr[$k][1]+1;
  }
 }
 //如果没有在数组里面出现
 if($bs==0)
 {
  $shuzu = array($code,1);
  $attr[] = $shuzu;
 }
 
 $_SESSION["gwc"]=$attr;
 
}
header("location:main.php");

gouwuche：

<div style="width:100%; height:100px;
 <h1 style="float:left">大苹果商城</h1>
    <a style="float:right; margin-top:40px" href="zhuxiao.php">注销</a>
</div>
<br />
<div style="width:100%; height:600px">
 <div id="left" style="width:20%; float:left">
     <a href="main.php"><div class="list">浏览商品</div></a>
        <a href="zhanghu.php"><div class="list">查看账户</div></a>
        <a href="gouwuche.php"><div class="list">查看购物车</div></a>
    </div>
   
 <div id="right" style="width:80%; float:left">
     <table width="100%" border="1" cellpadding="0" cellspacing="0">
        <tr>
         <td>商品名称</td>
            <td>商品单价</td>
            <td>购买数量</td>
            <td>操作</td>
        </tr>
       
        <?php
  include("../DBDA.class.php");
  $db = new DBDA();
  $attr=array();
  if(!empty($_SESSION["gwc"]))
  {
   $attr = $_SESSION["gwc"];
  }
  
  foreach($attr as $k=>$v)
  {
   $sql = "select name,price from fruit where ids='{$v[0]}'";
   $ashuiguo = $db->Query($sql);
  
   echo "<tr><td>{$ashuiguo[0][0]}</td><td>{$ashuiguo[0][1]}</td><td>{$v[1]}</td><td><a href='shanchu.php?sy={$k}'>删除</a></td></tr>";
   
  }
  
  ?>
       
        </table>
        <div id="tj">提交订单</div><div id="ts"></div>
    </div>
</div>

<script type="text/javascript">
$("#tj").click(function(){
  $.ajax({
    url:"dingdan.php",
    dataType:"TEXT",
    success: function(data){
      if(data.trim()=="OK")
      {
       alert("购买成功");
      }
      else if(data.trim()=="YEBUZU")
      {
       $("#ts").html("余额不足");
       $("#ts").css("color","red");
      }
      else
      {
       $("#ts").html(data);
       $("#ts").css("color","red");
      }
     }
   });
 })
</script>

dingdan：

<?php
session_start();
include("../DBDA.class.php");
$db = new DBDA();
$uid = $_SESSION["uid"];
$attr = array();
if(!empty($_SESSION["gwc"]))
{
 $attr = $_SESSION["gwc"];
}
//看下两个条件是否都满足
$bs = true;

//判断余额是否满足
 //根据用户名找余额
 $syue = "select account from login where username='{$uid}'";
 $yue = $db->StrQuery($syue);
 
 //根据购物车数组取总金额
 $sum = 0;
 foreach($attr as $v)
 {
  $sql = "select price from fruit where ids='{$v[0]}'";
  $danjia = $db->StrQuery($sql);
  $sum = $sum +$danjia*$v[1];
 }
 if($yue<$sum)
 {
  $bs = false;
  echo "YEBUZU";
  exit;
 }
 
//判断库存是否满足

foreach($attr as $v)
{
 $skucun = "select name,numbers from fruit where ids='{$v[0]}'";
 $akucun = $db->Query($skucun);
 if($akucun[0][1]<$v[1])
 {
  $bs = false;
  echo "{$akucun[0][0]}库存不足！";
  exit;
  
 }
}

//添加订单，减库存，减余额

if($bs)
{
 //减库存
 foreach($attr as $v)
 {
  $sql = "update fruit set numbers = numbers-{$v[1]} where ids='{$v[0]}'";
  $db->Query($sql,0);
 }
 
 //减余额
 $jianyue="update login set account=account-{$sum} where username='{$uid}'";
 $db->Query($jianyue,0);
 
 //添加订单
 $dingdanhao = $uid+date("YmdHis");
 $t = time();
 
 $sorder = "insert into orders values('{$dingdanhao}','{$uid}','{$t}')";
 $db->Query($sorder,0);
 
 foreach($attr as $v)
 {
  $sxq = "insert into orderdetails values('','{$dingdanhao}','{$v[0]}','{$v[1]}')";
  $db->Query($sxq,0);
 }
}

echo "OK";

shanchu：

<?php
session_start();

$sy = $_GET["sy"];

$attr = $_SESSION["gwc"];

if($attr[$sy][1]>1)
{
 $attr[$sy][1] = $attr[$sy][1]-1;
}
else
{
 unset($attr[$sy]);
 $attr = array_values($attr);
}

$_SESSION["gwc"]=$attr;

header("location:gouwuche.php");