<?php $action = trim($_GET['action']); if($action == "sub") { $str = $_POST['dir']; $str=iconv('GBK','utf-8',$str); //if(!preg_match("/^[".chr(0xa1)."-".chr(0xff)."A-Za-z0-9_]+$/",$str)) //GB2312汉字字母数字下划线正则表达式 //preg_match("/^[x{4e00}-x{9fa5}]+$/u",$str) if(!preg_match("/^[x{4e00}-x{9fa5}]+$/u",$str)) //UTF-8汉字正则表达式 { echo"<font color=red>您输入的[".$str."]含有违法字符</font>"; } else { echo "<font color=green>您输入的[".$str."]完全合法,通过!</font>"; } } ?> <!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <form method="POST" action="?action=sub"> 输入字符(数字,字母,汉字,下划线): <input type="text" name="dir" value=""> <input type="submit" value="提交"> </form> </body> </html>