PHP example code to implement user login cases

This article mainly introduces the PHP implementation of user login case code, small series feel very good, now share to everyone, but also for everyone to do a reference. Let's take a look at it with a little knitting.

This article describes the case code for PHP to implement user login. Share to everyone for your reference, as follows:

Requirements Analysis:

In Web application development, it is often necessary to implement the function of user login. Suppose a user named username, when the user enters the homepage of the site, if not logged in, the page will prompt to log in, the user entered the login information to verify, verify by entering the user center, otherwise display user name or password error, re-login. After successful login, the user can also click "Logout" to return to the login page.

Programming Flowchart:

Login.html

<! DOCUMENT HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "http://www.w3.org/tr/xhtml1/dtd/ Xhtml1-transitional.dtd "> 


login.php



<?php header ("Content-type:text/html;charset=utf-8");  Session_Start ();   if (isset ($_post[' login ')) {$username = Trim ($_post[' username '));   $password = Trim ($_post[' password '); if ($username = = ") | |   ($password = = "))    {Header (' refresh:3;url=login.html ');    echo "User name or password can not be empty, 3 seconds after jumping to the login page";   Exit } else if ($username! = ' username ') | |   ($password! = ' password '))    {//Username or password error header (' refresh:3;url=login.html ');    echo "User name or password error, 3 seconds after the jump to the login page";   Exit } else if (($username = = ' username ') && ($password = = ' password ')) {//login successfully saved information to SESSION $_session[' username ']    = $username;    $_session[' IsLogin ']=1;     If the tick is automatically saved within 7 days, save it to the cookie if ($_post[' Remember ']== "yes") {Setcookie ("username", $username, Time () +7*24*60*60);    Setcookie ("Code", MD5 ($username. MD5 ($password)), Time () +7*24*60*60);     } else {Setcookie ("username", "", Time ()-1);    Setcookie ("Code", ", Time ()-1);   }//Jump to the user Homepage header (' refresh:3;url=index.php '); }}?>


index.php



<?php  Header ("Content-type:text/html;charset=utf-8");  Session_Start ();  First determine if the COOKIE has the remember user information  if (isset ($_cookie[' username '))  {   $_session[' username ']=$_cookie[' username '] ;   $_session[' IsLogin ']=1;  }  if (Isset ($_session[' IsLogin '))  {   //already signed in   to echo $_session[' username ']. ": Hello, Welcome to the personal center! <br/> ";   echo "<a href= ' logout.php ' > Logout </a>";  }  else  {//For login   echo "You are not yet logged in, please <a href= ' login.html ' > Login </a>";  }?>


logout.php



<?php  Header ("Content-type:text/html;charset=utf-8");  Session_Start ();  Clear SESSION  $username =$_session[' username '];  $_session=array ();  Session_destroy ();  Clear Cookie  Setcookie ("username", "', Time ()-1);  Setcookie ("Code", ", Time ()-1);  echo "$username, welcome to the next visit";  echo "re-<a href= ' login.html ' > Login </a>";?>


Login interface:




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