<div>用户名：<input type="text" id="uid" /></div>
<div>密码：<input type="text" id="pwd" /></div>
<input type="button" value=http://www.mamicode.com/"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");
                }
                }
        });
    
    })


登陆主页面


<?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";
}


登陆处理页面



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

<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; background-color:#6CC">
    <h1 style="float:left">大苹果商城</h1>
    <a style="float:right; margin-top:40px" href=http://www.mamicode.com/"zhuxiao.php">注销</a>
</div>
<br />
<div style="width:100%; height:600px">
    <div id="left" style="width:20%; float:left">
        <a href=http://www.mamicode.com/"main.php"><div class="list">浏览商品</div></a>
        <a href=http://www.mamicode.com/"zhanghu.php"><div class="list">查看账户</div></a>
        <a href=http://www.mamicode.com/"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=http://www.mamicode.com/‘goumai.php?code={$v[0]}‘>购买</a></td></tr>";
        }
        ?>
        
        </table>
    </div>
</div>

*//主页面




<?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");


购买页面


<?php
session_start();
?>
//开启session
<style type="text/css">
.list{ width:100%; height:30px; margin-top:10px; text-align:center; line-height:30px; vertical-align:middle}
</style>
css样式
<div style="width:100%; height:100px; background-color:#6CC">
    <h1 style="float:left">大苹果商城</h1>
    <a style="float:right; margin-top:40px" href=http://www.mamicode.com/"zhuxiao.php">注销</a>
</div>
<br />
<div style="width:100%; height:600px">
    <div id="left" style="width:20%; float:left">
        <a href=http://www.mamicode.com/"main.php"><div class="list">浏览商品</div></a>
        <a href=http://www.mamicode.com/"zhanghu.php"><div class="list">查看账户</div></a>
        <a href=http://www.mamicode.com/"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>{$v[1]}</td><td><a href=http://www.mamicode.com/‘shanchu.php?sy={$k}‘>删除";
            
        }
        
        ?>
        
        </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>

//购物车页面

<?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");

//删除页面

<?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";
//订单页面






<script src=http://www.mamicode.com/"../../jquery-1.11.2.min.js"></script>