<?php 
session_start(); 
$_SESSION['username']="zhuzhao"; 
?>

<?php 
session_start(); 
unset($_SESSION['username']); 
if(isset($_SESSION['username'])) 
echo "username已经存在"; 
else 
echo "username不存在"; 
?>

php session处理的定制
user-define-session-inc.php文件代码：?phpfunctionmysession_open($save_path,$session_name){@mysql_connect("localhost","root","1981427")//选择数据库之前需要先连接数据库服务器ordie

php session应用实例 登录验证
htmlheadtitleLogin/titlemetahttp-equiv="Content-Type"content="text/html;charset=gb2312"/headbodyformname="form1"method="post"action="login.php"tablewidth="300"border="0"align="center"cellpadding="2"ce

php cookis创建实现代码
?phpsetcookie("username","zhuzhao",time()+10);//设置cookis保存5秒??phpif(isset($_COOKIE["username"])){echo$_COOKIE["username"];}else{echo"cookie没有找到";}?