主页代码：
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>PHP表单验证</title>
<style>
body{
margin: 0;
padding: 0;
background-color:powderblue;
}
.box{
width: 600px;
height: 330px;
margin: 100px auto;
padding-top: 10px;
background-color: white;
}
.reg{
color: red;
font-size: 1.5em;
}
input{
background: #eeeeee0f;
border-radius: 5px;
padding-left: 5px;
border: 1px solid #3a6c7e;
font-size: 100%;
outline: 0;
font-family: 微软雅黑;
line-height: 1.5;
}
#on{
display: block;
width: 30%;
height: 40px;
background-color: sandybrown;
border-radius: 5px;
font-size: 16px;
color: #fff;
text-align: center;
line-height: 40px;
}
#select {
font-size: 100%;
border-radius: 5px;
width: 20%;
background: #eeeeee0f;
border-radius: 5px;
padding-left: 5px;
border: 1px solid #3a6c7e;
</style>
</head>
<body>
<div class="box">
<form action="check.php" method="post">
<fieldset>
<legend class="reg">注册</legend>
<p>
<labal>用户：<input type="text" name="name"></labal>
</p>
<p>
<labal>邮箱：<input type="text" name="email"></labal>
</p>
<p>性别：
<input type="radio" name="gender" value="man">帅哥
<input type="radio" name="gender" value="woman">美女
<input type="radio" name="gender" value="shemale">待定
</p>
<p>
<label>年龄：
<select id="select" name="age">
<option value="1">30以内</option>
<option value="2">30到60</option>
<option value="3">60以上</option>
</select>
</label>
</p>
<p>备注：
<textarea name="comments" id="" cols="30" rows="5"></textarea>
</p>
</fieldset>
<p align="center"> <input id="on" type="submit" name="submit" value="提交"></p>
</form>
</div>
</body>
</html>验证php代码
<?php
header('Content-type:text/html;Charset=utf-8');
//1.先检查变量name（用户名）存不存在,存在返回name,否则返回null
$name=isset($_REQUEST['name'])? $_REQUEST['name'] :null;
//2.再判断用户名是否为空
if(empty($name)){
echo '<script>alert("您没有输入用户名")</script>>';
}else{
echo '<script>alert("您的用户名是'.$name.'");location.back()</script>>';
}
$email=isset($_REQUEST['email'])? $_REQUEST['email'] :null;
if(empty($email)){
echo '<script>alert("您没有输入邮箱")</script>>';
}else{
echo '<script>alert("您的邮箱是'.$email.'");location.back()</script>>';
}
$gender=isset($_REQUEST['gender'])? $_REQUEST['gender']:null;
switch ($gender){
case 'man':
echo '<script>alert("我是大帅哥")</script>>';
break;
case 'woman':
echo '<script>alert("我是来你们的女神")</script>>';
break;
case 'shemale':
echo '<script>alert("我来自泰国")</script>>';
break;
default:
echo '<script>alert("我可男可女，人送外号：大屌萌妹")</script>>';
}
$age=$_REQUEST['age']? $_REQUEST['age']:null;
switch ($age){
case '1':
echo '<script>alert("我30以内")</script>>';
break;
case '2':
echo '<script>alert("我年龄30到60之间")</script>>';
break;
case '3':
echo '<script>alert("我年龄60以上")</script>>';
break;
default:
echo '<script>alert("知道我多大了吗？")</script>>';
}
$comments=isset($_REQUEST['comments'])? $_REQUEST['comments']:null;
if(empty($comments)){
echo '<script>alert("你还没有编辑内容哦")</script>>';
}else{
echo '<script>alert("你编辑的文本内容是：'.$comments.'")</script>>';
}