一天一篇之php学习篇2
今天简单的写了下php后台登录,所使用的方法为 $_post,$_SESSION,及数据库连接,刚开始对session的定义不是很清楚,查看了帮助文档,里面的定义为'当前脚本可用 SESSION 变量的数组',解释的很抽象,其实session就是客户端与服务端会话,当session_start()运行的时候,在服务器产生了一个session文件,随之也产生了唯一一个对应的session id,$_SESSION['client']客户端注册一把钥匙来打开服务端的锁。
以下代码检测可用
1 <?php 2 if(isset($_POST["submit"])) 3 { 4 $username = $_POST['user'];//用户名 5 $pwd = $_POST['pwd'];//密码 6 7 /*数据库连接方法*/ 8 $hostname = 'localhost'; 9 $user = "root"; 10 $password = "root"; 11 $link = mysql_connect($hostname,$user,$password); 12 //mysql_query("set names utf-8"); 13 mysql_select_db('cms',$link);//选择库名 14 $query = "select * from admin where username = '$username' and password = '$pwd'"; 15 $rs = mysql_query($query);//执行查询 16 if(mysql_num_rows($rs) == 1) 17 { 18 $_SESSION['pwd'] = $_POST['pwd'];//数据匹配 19 $_SERVER['admin'] = session_id(); 20 echo "<script>alert('登录成功');window.location = 'admin_index.php';</script>"; 21 } 22 } 23 ?> 24 25 <?php 26 /*退出系统*/ 27 if(!empty($_GET['tj'])) 28 { 29 session_start(); 30 session_destroy(); 31 echo "<script>alert('退出成功');window.location = 'admin.php';</script>"; 32 33 } 34 ?> 35 36 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 37 <html xmlns="http://www.w3.org/1999/xhtml"> 38 <head> 39 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 40 <title>cms管理系统</title> 41 <style> 42 body{background:#ccc;} 43 input{display:block; margin:10px 0;} 44 </style> 45 </head> 46 47 <body> 48 <form action="" method="post" name="frm" id="frm"> 49 <label>用户名:<input type="text" size="20" maxlength="20" name="user" /></label> 50 <label>密 码:<input type="password" name="pwd" /></label> 51 <input type="submit" value="登录" name="submit" /> 52 </form> 53 <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.0/jquery.min.js"></script> 54 <script> 55 jQuery.fn.center = function () { 56 this.css("position","absolute"); 57 this.css("top", ( $(window).height() - this.height() ) / 2+$(window).scrollTop() + "px"); 58 this.css("left", ( $(window).width() - this.width() ) / 2+$(window).scrollLeft() + "px"); 59 return this; 60 } 61 $('#frm').center(); 62 </script> 63 64 </body> 65 </html>
数据库片段