初学php做了一些比较常见且有用的页面，放在上面记录一下咯
我是用了bootstrap框架里面的模态框做注册登陆页面，这样页面比较美观
页面效果：


注册成功条件/功能：
1）用户名不能冲突

2）两次密码必须相同

3）用户注册数据添加进数据库
4）注册/登录成功之后，用户自动登录

HTML代码：

    <link rel="stylesheet" href="css/bootstrap.css"><li class="toggle"><a data-toggle="modal" href="#loginer">登录</a></li><li class="toggle"><a data-toggle="modal" href="#register">注册</a></li><li class="toggle hidden"><a id="nicheng" href="##"></a></li><li class="toggle hidden"><a id="logout" href="##">注销</a></li>
//登录模态框
<div id="loginer" class="modal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel1"aria-hidden="true"><div class="modal-dialog"><div class="modal-content"><div class="modal-header"><button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button><h4 class="modal-title">请登录</h4></div><form id="form_login" class="form-horizontal"><div class="modal-body"><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="zh1">用户名：</label><div class="col-sm-9 require"><input type="text" class="form-control" name="username" id="zh1"pattern="\w{6,10}" required></div></div><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="pw1">密码：</label><div class="col-sm-9 require"><input type="password" pattern="\w{6,10}" class="form-control" name="pwd" id="pw1"required></div></div><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="yzm">验证码：</label><div class="col-sm-5 require"><input type="text" pattern="\d{4}" class="form-control" name="yzm" id="yzm"required></div><div class="col-sm-4"><img src="php/idcode.php" alt=""></div></div><div class="form-group has-feedback"><label id="info" class="col-sm-4 control-label pull-left"></label></div></div><div class="modal-footer"><button type="submit" class="btn btn-primary">登录</button><button type="button" class="btn btn-default" data-dismiss="modal">关闭</button></div></form></div></div>
</div>
//注册模态框
<div id="register" class="modal" tabindex="-1" role="dialog" aria-labelledby="myModalLabe2"aria-hidden="true"><div class="modal-dialog"><div class="modal-content"><div class="modal-header"><button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button><h4 class="modal-title">请注册</h4></div><form id="form_regist" class="form-horizontal"><div class="modal-body"><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="zh2">用户名：</label><div class="col-sm-9 require"><input type="text" class="form-control" name="username" id="zh2"pattern="\w{6,10}" required></div></div><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="pw2">密码：</label><div class="col-sm-9 require"><input type="password" pattern="\w{6,10}" class="form-control" name="pwd" id="pw2"></div></div><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="pw3">确认密码：</label><div class="col-sm-9 require"><input type="password" pattern="\w{6,10}" class="form-control" name="repwd" id="pw3"></div></div><div class="form-group has-feedback"><label class="col-sm-3 control-label" for="lc">昵称：</label><div class="col-sm-9 require"><input type="text" pattern="\S{2,10}" class="form-control" name="nc" id="lc"></div></div><div class="form-group has-feedback"><label id="wanner" class="col-sm-4 control-label pull-left"></label></div></div><div class="modal-footer"><button type="submit" class="btn btn-primary">注册</button><button type="button" class="btn btn-default" data-dismiss="modal">关闭</button></div></form></div></div>
</div>

JS代码：

<script src="js/jquery-2.1.3.js"></script>
<script src="js/bootstrap.min.js"></script>
<script>function toggle(){$.getJSON("php/get.php",function (res) {//获取当前用户是否登录if(res['flag']){//用户已经登录，显示昵称和注销选项$('li.toggle').toggleClass('hidden');$('#nicheng').html(res['nc'])}});}$('#form_login').submit(function (e) {/*登录*/e.preventDefault();/*阻止表单默认事件，页面全局刷新*/var data=$('#form_login').serialize();/*将表单里的数据包装起来*/$.getJSON('php/login.php',data,function (res) {/*data：将表单里的数据传给php，回调函数接受php返回来的值*/if(res==3){//用户名、密码、验证码都输入正确toggle();/*修改首页选项菜单*/$('#loginer').modal('hide');/*关闭模态框*/}else if(res==2){$('#info').html('用户名或密码有误')}else {$('#info').html('验证码有误')}})});$('#logout').click(function () {confirm('确定要注销？');$.getJSON('php/logout.php',function (res) {if(res)toggle();})})$('#form_regist').submit(function (e) {e.preventDefault();var data=$('#form_regist').serialize();$.getJSON('php/regist.php',data,function (res) {if(res==3){toggle();$('#register').modal('hide');}else if (res==2) {$('#wanner').html('两次密码不一致，请重试！')}else if (res==1) {$('#wanner').html('用户名冲突，请重试！')}})});

connect.php(连接数据库)：

<?php
$link=new PDO("mysql:host=localhost;port=3306;dbname=db","root","");
$link->query("set names utf8");

get.php(判断登录状态)：未登录显示登录注册选项，用户登陆后切换显示成昵称和注销选项

<?php
include_once ("connect.php");
session_start();/*开启会话*/
if (isset($_SESSION['username'])){/* 判断用户会话里用户名是否存在，即用户是否登录*/$json['nc']=$_SESSION['nc'];/*把昵称存起来，一会返回给首页*/$json['flag']=true;/*用户已经登录，标志flag为true*/
}else$json['flag']=false;/*用户已经登录，标志flag为true*/
echo json_encode($json);/*返回json*/

regist.php(注册)：根据设置标志flag的值判断注册的三种状态

<?php
include_once ("connect.php");
$user=$_GET['username'];//获取表单提交的数据
$pwd=$_GET['pwd'];
$repwd=$_GET['repwd'];
$nc=$_GET['nc'];
$row=$link->query("select * from `user` where username='$user'");
/*查询数据库中是否存在用户名相同的用户*/
if ($row->rowCount()){$flag=1;/*存在用户名相同，即用户名冲突*/
}else if ($pwd!=$repwd){$flag=2;/*两次密码不相同*/
}else{/*插入数据进数据库*/$row=$link->exec("insert into`user`( `username`,  `pwd`，`nc`) values ('$user','$pwd','$nc')");session_start();/*打开会话，将用户名和昵称存起来*/$_SESSION['username']=$user;$_SESSION['nc']=$nc;$flag=3;/*注册成功标志*/
}
echo $flag;

login.php(登录)：根据标志flag判断登录操作是否成功或哪里出错

<?php
include_once ("connect.php");
session_start();/*开启会话*/
$user=$_GET['username'];/*获取登录表单提交过来的数据*/
$pwd=$_GET['pwd'];
$yzm=$_GET['yzm'];
if($yzm==$_SESSION['vCode']){/*当用户输入的验证码和图片验证码相同时*/$result=$link->query("select * from `user` where username='$user' and pwd='$pwd'");$link = null;$row = $result->fetch();/*读取从数据库获取的数据*/if ($row) {/*如果数据存在，即用户登录成功*/$_SESSION['username'] = $row['username'];/*将用户名和昵称存在服务器，可以多个页面使用*/$_SESSION['nc'] = $row['nc'];$flag=3;}else{/*用户名或密码错误*/$flag=2;}
}else{/*验证码输入错误*/$flag=1;
}
echo $flag;

logout.php(注销登录)：直接销毁会话变量，然后get.php里面获取不到username和nc即判断用户已注销

<?php
session_start();
unset($_SESSION['username']);//销毁用户名
unset($_SESSION['nc']);//销毁昵称
echo json_encode(true);//返回结果

登录页面的自动生成验证码代码，在我的另一篇文里
https://www.cnblogs.com/xyyl/p/10901100.html