本节我们创建一个login.php文件，显示完整的登录功能代码
前面我们创建了style.css文件，把这个CSS文件放在同一文件夹目录下，直接调用CSS样式。
引入数据库公共文件config.php。
<?php
require_once("config.php"); //引入数据库文件
?>
<?php
if($_POST["Submit"])
{
$username=$_POST["username"];
$pwd=$_POST["pwd"];
$code=$_POST["code"];
if($code<>$_SESSION["auth"])
{
echo "<script language=javascript>alert('验证码不正确！');window.location='login.php'</script>";
?>
<?php
die();
}
$SQL ="SELECT * FROM admin where username='$username' and password='$pwd'";
$rs=mysqli_query($link,$sql);
if(mysqli_num_rows($rs)==1)
{
$_SESSION["pwd"]=$_POST["pwd"];
$_SESSION["admin"]=session_id();
echo "<script language=javascript>alert('登陆成功！');window.location='admin_index.php'</script>";
}
else
{
echo "<script language=javascript>alert('用户名或密码错误！');window.location='login.php'</script>";
?>
<?php
die();
}
}
?>
<?php
if($_GET['tj'] == 'out'){
session_destroy();
echo "<script language=javascript>alert('退出成功！');window.location='login.php'</script>";
}
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>图书后台管理系统登陆功能</title>
<!-- 引入CSS样式 -->
<link rel="stylesheet" type="text/css" href="style.css"/>
</head>
<body>
<div id="top"> </div>
<form id="frm" name="frm" method="post" action="" onSubmit="return check()">
<div id="center">
<div id="center_left"></div>
<div id="center_middle">
<div class="user">
<label>用户名：
<input type="text" name="username" id="username" />
</label>
</div>
<div class="user">
<label>密 码：
<input type="password" name="pwd" id="pwd" />
</label>
</div>
<div class="chknumber">
<label>验证码：
<input name="code" type="text" id="code" maxlength="4" class="chknumber_input" />
</label>
<img src="verify.php" style="vertical-align:middle" />
</div>
</div>
<div id="center_middle_right"></div>
<div id="center_submit">
<div class="button"> <input type="submit" name="Submit" class="submit" value=" ">
</div>
<div class="button"><input type="reset" name="Submit" class="reset" value=""> </div>
</div>
<div id="center_middle_right"></div>
</div>
</form>
<div id="footer"></div>
</body>
</html>
nächsten Abschnitt