正则表达式验证IP地址

来源：互联网发布：东北财经大学就业知乎编辑：程序博客网时间：2024/05/30 13:41

一代码

<!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=gb2312" /><title>应用正则表达中的点字符（.）</title><style type="text/css"><!--body {margin-left: 0px;margin-top: 0px;margin-right: 0px;margin-bottom: 0px;}--></style></head><body><?php $checkip="/^(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])(\.)(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])(\.)(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])(\.)(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])$/";if($_POST[check_ip]!="" and $_POST[Submit]=="提交"){if(preg_match($checkip,$_POST[check_ip],$counts)){echo "<script>alert('IP地址格式正确!');window.location.href='index.php';</script>"; }else{echo "<script>alert('IP地址格式不正确!');window.location.href='index.php';</script>"; }}?><table width="851" height="483" border="0" align="center" cellpadding="0" cellspacing="0" background="images/bg.jpg">  <tr>    <td height="119" colspan="3">&nbsp;</td>  </tr><form id="form1" name="form1" method="post" action="index.php">  <tr>    <td width="336" height="264">&nbsp;</td>    <td width="260" align="center" valign="top">IP地址：      <input type="text" name="check_ip" /></td>    <td width="255" valign="top"><input type="submit" name="Submit" value="提交" /></td>  </tr></form>  <tr>    <td height="100">&nbsp;</td>    <td>&nbsp;</td>    <td>&nbsp;</td>  </tr></table></body></html>

二运行结果

输入：56.06.45.33

输出：IP地址格式不正确

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