初学者做的东西，有的地方写的不好，哈哈哈！
一.知识重点
1.三目运算 $page= empty($_GET[‘p‘]) ? 1: $_GET[‘p‘];
2.数据库的操作mysqli的方法
3.html css js
4.字符串的拼接
5.制作分页页码
6.完整验证码的制作
7.类的运用
8.session传递验证码的方法
二 .代码
代码分为6个文件，liuyanbook.php为主页
1.liuyanbook.php主界面
<?php//日期$weekday = ["日","一","二","三","四","五","六"];date_default_timezone_set(‘Asia/Shanghai‘); $now = getdate(time());$week=$now[‘wday‘];$date = date("Y年m月d日 ?星期$weekday[$week]");//echo $date;//设置页码变量//默认首页p=1$page= empty($_GET[‘p‘]) ? 1: $_GET[‘p‘];//页码$showPage = 3;//计算偏移量$pageoffset = ($showPage-1)/2;//连接数据库，取数据$host = "127.0.0.1";$dbuser = "root";$password = "";$dbname = "php10";$db = new mysqli($host, $dbuser, $password, $dbname);if ($db->connect_errno != 0) { ???echo "连接失败:"; ???echo $db->connect_error; ???exit;}//分页$db->query("set names utf8");$limit = ?($page-1) * 5;$sql = "select * from msg order by id desc limit {$limit},5";$mysqli_result = $db->query($sql);if ($mysqli_result == false) { ???echo "SQL错误！"; ???exit;}//var_dump($mysqli_result);//总页数$total_sql = "select count(*) from msg";$total_result = $db->query($total_sql);$total_array = mysqli_fetch_array($total_result,MYSQLI_ASSOC);$total = $total_array["count(*)"];//echo $total;//计算页数$total_pages = ceil($total/5);//echo $total_pages;?><!DOCTYPE html><html><head> ???<meta charset="UTF-8"/> ???<title>三态电子商务有限公司</title> ???<link rel="stylesheet" type="text/css" href="style.css"/> ???<script type="text/javascript"></script></head><body><div class="contentout"> ???<div class="date"><?php echo $date;?></div> ???<div class="h"> ???????<h1>三态电子商务有限公司</h1> ???????<h2>留言板</h2> ???</div> ???<div class="all"> ???????<div class="add"> ???????<form action="liuyan.php" method="post"> ???????????<textarea name="content" class="content" cols="60" rows="8"></textarea><br> ???????????留言人：<input style="padding:6px 8px"; name="user" class="user" type="text"/> ???????????<p>验证码图片：<img id="captcha_img" border="1" src="str.php?r=<?php echo rand();?>" width="100px" height="30"</p> ???????????<a href="javascript:void(0)" onclick="document.getElementById(‘captcha_img‘).src=‘str.php?r=‘+Math.random()">换一个？</a> ????????????请输入图片中的内容：<input style="padding:6px 8px"; type="text" name="authcode" value="" /> ???????????<input class="btn" type="submit" value="提交留言"/> ???????</div> ???????</form> ???????<!--留言内容--> ???????<?php ???????while($row = mysqli_fetch_array($mysqli_result,MYSQLI_ASSOC)) { ????????> ???????????<div class="msg"> ???????????????<div class="info"> ???????????????????<span class="user"><?php echo $row["user"];?></span> ???????????????????<span class="num"><?php echo " ".$row["id"]."楼";?></span> ???????????????????<span class="time"><?php echo date("Y-m-d H:i:s",$row["intime"]);?></span> ?????????????????</div> ???????????????<div class="content"> ???????????????????<?php echo $row["content"];?> ??????????????????</div> ???????????</div> ???????<?php ???????} ????????> ???</div> ???//页码部分 ???<div class="page"> ???<?php ???????$page_banner = ""; ???????if ($page > 1) { ???????????$page_banner = "<a href=‘liuyanbook.php?p=1‘>首页</a>"; ???????????$page_banner.= " "."<a href=‘liuyanbook.php?p=".($page-1)."‘>上一页</a>"; ???????} ???????//初始化前面页码数据 ???????$start = 1; ???????$end = $total_pages; ???????if ($total_pages > $showPage) { ???????????if($page > $pageoffset + 1) { ???????????????$page_banner.="..."; ???????????} ???????????if ($page > $pageoffset) { ???????????????$start = $page - $pageoffset; ???????????????$end = $total_pages > $page + $pageoffset ? $page + $pageoffset : $total_pages; ???????????} else { ???????????????$start = 1; ???????????????$end = $total_pages > $showPage ? $showPage : $total_pages; ???????????} ???????????if ($page + $pageoffset > $total_pages) { ???????????????$start = $start - ($page + $pageoffset - $total_pages); ???????????} ???????} ???????//显示前面的页码 ???????for($i=$start;$i<$end;$i++) { ???????????$page_banner.= " "."<a href=‘".$_SERVER[‘PHP_SELF‘]."?p=".$i."‘>{$i}</a>"; ???????} ???????//显示尾部省略 ???????if ($total_pages > $showPage && $total_pages > $page + $pageoffset) { ???????????$page_banner.="..."; ???????} ???????if ($page < $total_pages) { ???????????$page_banner.= " "."<a href=‘".$_SERVER[‘PHP_SELF‘]."?p=".($page+1)."‘>下一页</a>"; ???????????$page_banner.= " "."<a href=‘liuyanbook.php?p=".$total_pages."‘>尾页</a>"; ???????} ???????//页码部分字符拼接 ???????$page_banner.= " "."共".$total_pages."页"; ???????$page_banner.= " "."共".$total."条留言"; ???????$page_banner.= "<form action=‘liuyanbook.php‘ method=‘get‘ style= display:inline>"; ???????$page_banner.= " "."跳转到第<input type=‘text‘ size=‘1‘ name=‘p‘>页"; ???????$page_banner.= "<input type=‘submit‘ value=‘确定‘>"; ???????$page_banner.= "</form>"; ???????echo ?$page_banner; ????> ???</div></div> ?</body></html>2.liuyan.php后端验证，插入数据
<?phpinclude(‘class_input.php‘);include(‘dbcontent.php‘);//include(‘str.php‘);$content = $_POST["content"];$user = $_POST["user"];$authcode = $_POST["authcode"];//不能为空/*if ($content == "") { ???die("留言内容不能为空！");}if ($user == "") { ???die("请输入留言人的姓名！");}*///对输入的内容和留言人进行检测，不能含有李星和王瑶两个名字$input = new input();//检测显示的结果$is = $input->post($content);if ($is == false) { ???die("留言内容不能为空或者存在禁止关键字!");}$is = $input->post($user);if ($is == false) { ???die("留言人不能为空或者存在禁止关键字！");}//检测验证码$codeinput = new codeinput();$iscode = $codeinput->check($authcode);if ($iscode == false) { ???die("请输入正确的验证码！");}//var_dump($content,$user);//将留言内容写入数据库$time = time();$sql = "insert into msg (content, user, intime) values (‘{$content}‘,‘{$user}‘,‘{$time}‘)";//echo $sql;$is = $db->query($sql);//var_dump($is);header("location:liuyanbook.php");//跳回主页?>3.class_input.php两个类，验证关键字和验证码的类
<?phpclass input { ???function post($word) { ???????if ($word == "") { ???????????return false; ???????} ???//定义禁止使用的用户 ???$name = ["李星","王瑶"]; ???//循环禁止使用的关键字，user一一与它对比 ???foreach ($name as $key => $value) { ???????if ($word == $value) { ???????????return false; ???????} ???} ???????????return true; ???}}class codeinput { ???function check($code) { ???????if ($code == "") { ???????????return false; ???????} ???//判断输入验证码是否正确 ???if (isset($code)) { ???session_start(); ???if (strtolower($code) == $_SESSION["authcode"]) { ???????return true; ???} else { ???????return false; ???} ???exit();} ??????}}?>4.dbcontent.php数据库连接
<?php$host = "127.0.0.1";$dbuser = "root";$password = "";$dbname = "php10";$db = new mysqli($host, $dbuser, $password, $dbname);if ($db->connect_errno != 0) { ???die("连接数据库失败！");}$db->query("set names UTF8");?>5.str.php生成验证码
<?phpsession_start();header("content-type: image/png"); ???//生成白色底图 ???$image = imagecreatetruecolor(100, 30); ???$bgcolor = imagecolorallocate($image, 255, 255, 255); ???imagefill($image, 0, 0, $bgcolor); ???//在白色底图上生成4个彩色随机字符 ???/*1.生成4个数字 ???for($i=0;$i<4;$i++) { ???????$fontsize = 6; ???????$fontcolor = imagecolorallocate($image, rand(0, 120), rand(0, 120), rand(0, 120)); ???????$fontcontent = rand(0, 9); ???????$x = ($i*100/4) + rand(5, 10); ???????$y = rand(5, 10); ???????imagestring($image, $fontsize, $x, $y, $fontcontent, $fontcolor); ???}*/ ???//2.生成随机字母数字 ???$captch_code = "";//将生成的验证码存入该变量中 ???for($i=0;$i<4;$i++) { ???????$fontsize = 6; ???????$fontcolor = imagecolorallocate($image, rand(0, 120), rand(0, 120), rand(0, 120)); ???????//随机截取字母数字 ???????$data = "abcdefghijkmnopqrstuvwxyz23456789"; ???????$fontcontent = substr($data,rand(0,strlen($data)),1); ???????$captch_code.= $fontcontent;//追加到验证码存放 ???????$x = ($i*100/4) + rand(5, 10); ???????$y = rand(5, 10); ???????imagestring($image, $fontsize, $x, $y, $fontcontent, $fontcolor); ???} ???$_SESSION["authcode"] = $captch_code;//保存到session中 ???//在白色底图上生成随机点(干扰元素) ???for($i=0;$i<200;$i++) { ???????$pointcolor = imagecolorallocate($image, rand(50, 200), rand(50, 200), rand(50, 200)); ???????imagesetpixel($image, rand(1, 29), rand(1, 29), $pointcolor); ???} ???//在白色底图上生成随机线(干扰元素) ???for($i=0;$i<3;$i++) { ???????$linecolor = imagecolorallocate($image, rand(80, 220), rand(80, 220), rand(80, 220)); ???????imageline($image, rand(1, 99), rand(1, 29), rand(1, 99), rand(1, 29), $linecolor); ???} ???imagepng($image); ???imagedestroy($image);?>6.style.css界面样式
.all { ???width: 800px; ???margin: 0px auto;}.contentout { ???width: 1000px; ???margin: 0 auto;}.date { ???text-align:right;}.h { ???text-align:center;}.add {overflow: hidden;}.add .content { ???width: 98%; ???padding: 6px; ???margin: 0px; ???font-size:20px; ???}.add .btn { ???float: right; ???width: 100px; ???height: 40px; ???font-size: 20px;}.msg { ???margin: 10px 0px; ???background: #ccc; ???padding: 10px; ???font-size: 18px;} .msg .info{overflow: hidden;}.msg .user { ???float: left; ???color: blue;}.msg .num { ????font-style: italic; ????font-size: 16px; ???color: red;} .msg .time { ???float: right; ???color: #999;}.msg .content { ???width: 100%;}.page { ???text-align:center; ???font-size: 18px;}``.all { ???width: 800px; ???margin: 0px auto;}.contentout { ???width: 1000px; ???margin: 0 auto;}.date { ???text-align:right;}.h { ???text-align:center;}.add {overflow: hidden;}.add .content { ???width: 98%; ???padding: 6px; ???margin: 0px; ???font-size:20px; ???}.add .btn { ???float: right; ???width: 100px; ???height: 40px; ???font-size: 20px;}.msg { ???margin: 10px 0px; ???background: #ccc; ???padding: 10px; ???font-size: 18px;} .msg .info{overflow: hidden;}.msg .user { ???float: left; ???color: blue;}.msg .num { ????font-style: italic; ????font-size: 16px; ???color: red;} .msg .time { ???float: right; ???color: #999;}.msg .content { ???width: 100%;}.page { ???text-align:center; ???font-size: 18px;}三.数据库
表结构
四.截图界面
PHP初级练习实战之公司留言板（原生）
原文地址：http://blog.51cto.com/anfishr/2141316