PHP登录验证功能示例【用户名、密码、验证码、数据库、已登陆验证、自动登录和注销登录等】

本文实例讲述了PHP登录验证功能。分享给大家供大家参考，具体如下：

登录界面

具体实现方法如下：

<!DOCTYPE html 
<html lang="en" 
<head 
  <meta charset="UTF-8" 
  <title Title</title 
</head 
<body 
<form method="post" action="doLogin.php" 
  <input type="text" placeholder="用户名" name="username" <br <br 
  <input type="password" placeholder="密码" name="password" <br <br 
  <input type="text" placeholder="验证码" name="verifycode" class="captcha" <br <br 
  <img id="captcha_img" src="captcha.php?r=<?php echo rand();? " alt="验证码" 
  <label <a href="javascript:void(0)" rel="external nofollow" onclick="document.getElementById('captcha_img').src='captcha.php?r='+Math.random()" 换一个</a  </label <br 
  <label <input type="checkbox" name="autologin[]" value="1"/ 自动登录</label <br 
  <button type="submit" 登录</button 
</form 
</body 
</html

doLogin.php

<?php
header("Content-type:text/html;charset=UTF-8");
require "mysql.php";      //导入mysql.php访问数据库
session_start();        //开启会话一获取到服务器端验证码
$username=$_POST['username'];
$password=$_POST['password'];
$autologin=isset($_POST['autologin'])?1:0;   //获取是否选择了自动登录
$verifycode=$_POST['verifycode'];
$code=$_SESSION['code'];    //获取服务器生成的验证码
/*
* 首先进行判空操作，通过后进行验证码验证，通过后再进行数据库验证。
* 手机号码和邮箱验证可根据需要自行添加
* */
if(checkEmpty($username,$password,$verifycode)){
if(checkVerifycode($verifycode,$code)){
if(checkUser($username,$password)){
$_SESSION['username']=$username; //保存此时登录成功的用户名
if($autologin==1){        //如果用户勾选了自动登录就把用户名和加了密的密码放到cookie里面
setcookie("username",$username,time()+3600*24*3);  //有效期设置为3天
setcookie("password",md5($password),time()+3600*24*3);
}
else{
setcookie("username","",time()-1);  //如果没有选择自动登录就清空cookie
setcookie("password","",time()-1);
}
header("location: index.php ");      //全部验证都通过之后跳转到首页
}
}
}
//方法：判断是否为空
function checkEmpty($username,$password,$verifycode){
if($username==null||$password==null){
echo '<html <head <Script Language="JavaScript" alert("用户名或密码为空");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";
}
else{
if($verifycode==null){
echo '<html <head <Script Language="JavaScript" alert("验证码为空");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";
}
else{
return true;
}
}
}
//方法：检查验证码是否正确
function checkVerifycode($verifycode,$code){
if($verifycode==$code){
return true;
}
else{
echo '<html <head <Script Language="JavaScript" alert("验证码错误");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";
}
}
//方法：查询用户是否在数据库中
function checkUser($username,$password){
$conn=new Mysql();
$sql="select * from user where name='{$username}' and password='{$password}';";
$result=$conn- sql($sql);
if($result){
return true;
}
else{
echo '<html <head <Script Language="JavaScript" alert("用户不存在");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";
}
$conn- close();
}
//方法：手机格式验证
function checkPhoneNum($phonenumber){
$preg="/^1[34578]{1}d{9}$/";
if(preg_match($preg,$phonenumber)){
return ture; //验证通过
}else{
echo '<html <head <Script Language="JavaScript" alert("手机号码格式有误");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";//手机号码格式不对
}
}
//方法：邮箱格式验证
function checkEmail($email){
$preg = '/^(w{1,25})@(w{1,16})(.(w{1,4})){1,3}$/';
if(preg_match($preg, $email)){
return true;
}else{
echo '<html <head <Script Language="JavaScript" alert("y邮箱格式有误");</Script </head </html ' . "<meta http-equiv="refresh" content="0;url=login.html" ";
}
}

logout.php

<?php
//退出登录并跳转到登录页面
unset($_SESSION['username']);
setcookie("username","",time()-1);  //清空cookie
setcookie("password","",time()-1);
header("location: login.html ");

index.php

<?php
session_start();
if(empty($_COOKIE['username'])&&empty($_COOKIE['password'])){
if(isset($_SESSION['username']))
echo "登录成功，欢迎您".$_SESSION['username']."<a href='logout.php' 退出登录</a ";
else
echo "你还没有登录，<a href='login.html' 请登录</a ";
}
else
echo "登录成功，欢迎您：".$_COOKIE['username']."<a href='logout.php' 退出登录</a ";

验证码和数据库的实现方法前面写过，这里不再赘述。

验证码制作：//www.zalou.cn/article/156850.htm 数据库连接：//www.zalou.cn/article/156875.htm