1.表单的验证的小案例
HTML表单
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> </head> <body> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>demo1.html</title> </head> <body> <form method="post" action="demo2.php"> 用户名:<input type="text" name="username" /><br/> 密 码: <input type="password" name="password" /><br/> 邮 箱:<input type="email" name="email" /><br/> 验证码:<input type="text" size="4" name="code"/><br/> <input type="submit" value="提交" name="send" /> </form> </body> </html> </body> </html>
demo2.php需要接收信息的页面
<?php
if(!isset($_POST[‘send‘]))
{
header(‘Location:demo3‘);
exit;
}
$username=htmlspecialchars(trim($_POST[‘username‘]));
$password=$_POST[‘password‘];
$email=htmlspecialchars(trim($_POST[‘email‘]));
$code=$_POST[‘code‘];
if(strlen($username)<2||strlen($username)>20)
{
echo"<script>alert(‘您输入的用户名不能小于2个字符或者大于20个字符‘);history.back()</script>";
}
if(strlen($password)<6||strlen($password)>10)
{
echo "<script>alert(‘您的密码不能小于6位或者大于10位‘);histroy.back()</script>";
}
$mode=‘/(^[\w\.]{1,20})+@+([\w]{2,})+[.]+([a-z]{2,5})/‘;//正则表达式验证邮箱
if(!preg_match($mode,$email))
{
echo "<script>alert(‘你输入的邮箱格式错误，请重新输入‘);history.back()</script>";
}
if(strlen($code)!=4||!is_numeric($code))
{
echo"<script>alert(‘你输入的验证码有误，请重新输入‘);history.back()</script>";
}
echo "您的用户名是:".$username.‘<br />‘.‘邮箱是:‘.$email;
?>
原文：http://www.cnblogs.com/niangaolizai/p/5719925.html