PHP開(kāi)發(fā)留言板教程之登錄功能
登錄功能：我們先來(lái)看以下html代碼
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>歡迎登錄</title>
<style type="text/css">
*{margin: 0px;padding: 0px;}
body{background:#eee;}
#div{width:300px;height:400px;background:#B1FEF9;margin:0 auto;margin-top:150px;
border-radius:20px;}
h3{margin-left:48px;padding-top:60px;}
h4{margin-left:120px;padding-top:60px;font-size: 18px;}
#cnt{width:280px;height:370px;margin-left:33px;padding-top:60px;}
.sub{width:70px;height:30px;border:1px solid #fff;background:#eee;
margin-left:28px;margin-top:20px;}
.sub1{
width:70px;height:30px;border:1px solid #fff;background:#eee;margin-left:150px;margin-top:20px;}
</style>
</head>
<body>
<div id="div">
<h3>歡迎登陸后臺(tái)管理系統(tǒng)</h3>
<div id="cnt">
<form method="post" action="main.php">
用戶名：<input type="text" placeholder="請(qǐng)輸入用戶名" name="username">
<br><br>
密 碼：<input type="password" placeholder="請(qǐng)輸入密碼" name="password">
<br><br>
<input type="submit" value="登錄" class="sub">
</form>
</div>
</div>
</body>
</html>表單提交到main.php 下面我們來(lái)分析一下main.php
當(dāng)我們登錄了之后，我們?nèi)绻泻荛L(zhǎng)一段事件沒(méi)有沒(méi)網(wǎng)頁(yè)進(jìn)行操作，當(dāng)你再次操作的時(shí)候需要去登錄，這個(gè)會(huì)用到我們的session的知識(shí)
首先我們要打開(kāi)session
????session_start();
然后我們要把鏈接數(shù)據(jù)庫(kù)的文件conn.php 引入進(jìn)來(lái)
????require_once('conn.php');
獲取表單的信息，然后把表單的信息存入session
????$name = $_POST['username'];
?? ?$pwd = md5($_POST['password']);
?? ?$_SESSION['name']=$name;
?? ?$_SESSION['pwd']=$pwd;
下面我們?nèi)?shù)據(jù)庫(kù)查詢，如果數(shù)據(jù)庫(kù)存在表單提交的信息，那么我們應(yīng)該是讓該表單提交的信息可以進(jìn)行登錄操作
????$sql = "select * from user where username='$name' and password='$pwd'";
?? ?$info = mysql_query($sql);
?? ?$row = mysql_fetch_row($info);
然后對(duì) $row 進(jìn)行判斷，存在，登錄成功，跳轉(zhuǎn)到首頁(yè)進(jìn)行添加留言的操作，否則，返回該頁(yè)面，進(jìn)行重新登錄
????if($row){
?? ??? ?echo "<script>alert('登錄成功');location.href='message.php';</script>";
?? ?}else{
?? ??? ?echo "<script>alert('登錄失敗')</script>";
?? ??? ?echo "<script>location.href='login.php';</script>";? //登錄失敗，跳轉(zhuǎn)到另外一個(gè)頁(yè)面
?? ?}
main.php 完整代碼如下：
<?php
session_start();
require_once('conn.php');
$name = $_POST['username'];
$pwd = md5($_POST['password']);
$_SESSION['name']=$name;
$_SESSION['pwd']=$pwd;
$sql = "select * from user where username='$name' and password='$pwd'";
$info = mysql_query($sql);
$row = mysql_fetch_row($info);
if($row){
echo "<script>alert('登錄成功');location.href='message.php';</script>";
}else{
echo "<script>alert('登錄失敗')</script>";
echo "<script>location.href='login.php';</script>"; //登錄失敗，跳轉(zhuǎn)到另外一個(gè)頁(yè)面
}
?>
