session_start();//开启session
HTTP,无状态性
SESSION COOKIE
SESSION：存储在服务端的，每个人存一份，可以存储任意类型的数据，默认过期时间15分钟
COOKIE：存储在客户端的，每个人存一份，只能存储字符串，默认永不过期
$_SESSION["uid"] = "zhangsan";//写入SESSION
echo $_SESSION["uid"];
setcookie("uid","zhangsan"); //设置COOKIE
例子：
denglu.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> </head> <body> <form action="chuli.php" method="post"> <div>用户名：<input type="text" name="uid" /></div> <div>密码：<input type="text" name="pwd" /></div> <div><input type="submit" value="登录" /></div> </form> </body> </html>
chuli.php
<?php session_start();//开启session $uid=$_POST["uid"]; $pwd=$_POST["pwd"]; include("ChaXun.class.php"); $db=new ChaXun(); $sql="select count(*) from User1 where Uid='{$uid}' and Pwd='{$pwd}'"; $r=$db->StrQuery($sql); if($r==1) { $_SESSION["uid"]=$uid;//存入session header("location:main.php"); } else { header("location:session.php"); }
main.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> </head> <body> <?php session_start(); echo $_SESSION["uid"]; ?> </body> </html>