终于懂浏览器里面的cookies和session了

在PHP开发中对比起Cookie，session 是存储在服务器端的会话，相对安全，并且不像 Cookie 那样有存储长度限制；

（Php、Asp、Jsp）---：

cookie（客户端）界面没有刷新的话，cookie在本页中是不会起作用的。

session（服务器）session默认是20分钟。

 1 <html>
 2 <head>
 3     <title>
 4 
 5     </title>
 6     <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
 7 </head>
 8 <?php
 9 session_start();
10 
11 if(isset($_POST['submit'])){
12     $user = $_POST['userName'];
13     $pass = $_POST['pass'];
14 
15     $conn = mysql_connect("localhost","root","root") or die("链接数据库失败");
16     mysql_select_db("test");
17     mysql_query("set names 'utf8'");
18 
19     $sql = "SELECT COUNT( * ) FROM users WHERE  `userName` =  '$user' AND  `pass` =  '$pass'";
20     $result = mysql_query($sql);
21     $row = mysql_fetch_row($result);
22 
23     if($row[0]){
24         $_SESSION["myname"] = $user;
25 
26     }
27 }
28 
29 if(isset($_SESSION['myname'])){
30     echo $_SESSION['myname'];
31 }
32 //unset($_SESSION['myname']);//关闭一个session
33 //session_destroy();//关闭多个session
34 ?>
35 
36 <body>
37     <form action="login_seesion.php" method="post">
38         用户名：<input type="text" size="10" name="userName" /><br>
39         密  码：<input type="text" name="pass" /><br/>
40         <input type="submit" name="submit" value="登录"/>
41     </form>
42 </body>
43 
44 </html>

 1 <html>
 2 <head>
 3     <title>cookie</title>
 4     <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
 5 </head>
 6 <?php
 7 setcookie("mycookie","");
 8 if(isset($_POST['submit'])){
 9     $user = $_POST['userName'];
10     $pass = $_POST['pass'];
11 
12     $conn = mysql_connect("localhost","root","root") or die("链接数据库失败");
13     mysql_select_db("test");
14     mysql_query("set names 'utf8'");
15 
16     $sql = "SELECT COUNT( * ) FROM users WHERE  `userName` =  '$user' AND  `pass` =  '$pass'";
17     $result = mysql_query($sql);
18     $row = mysql_fetch_row($result);
19 
20     if($row[0]){
21         setcookie("mycookie",$user,time()+1800);
22     }
23 }
24 ?>
25 <body>
26 <?php
27 if(isset($_COOKIE['mycookie'])){
28     echo "欢迎你:".$_COOKIE['mycookie'];
29 }else{
30 ?>
31 
32 <form action="login.php" method="post">
33     用户名：<input type="text" size="10" name="userName" /><br>
34     密  码：<input type="text" name="pass" /><br/>
35     <input type="submit" name="submit" value="登录"/>
36 </form>
37 <?php
38 }
39 ?>
40 </body>
41 </html>