php如何获取submit里面的值

 <!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>无标题文档</title>
</head>

<body>

<body>
<form action="12321.php" method="get">
名字: <input type="text" name="fname"><br/>
年龄: <input type="text" name="age"><br/>
<input type="submit" value="提交" name="submit">
</form><br/>

<?php
$a=$_GET["fname"];
$b=$_GET["age"];
$c=$_POST[submit];
var_dump($c);
echo "</br>";
if(isset($c)){
 echo "欢迎".$a."</br>";
 echo "年龄".$b."</br>";
 }else
 {
 echo "欢迎光临";
 }
 ?> 
</body>
</html>

此文件的文件名是 12321.php
报错如下：
Notice: Undefined index: fname in F:\php\www\12321.php on line 18

Notice: Undefined index: age in F:\php\www\12321.php on line 19

Notice: Use of undefined constant submit - assumed 'submit' in F:\php\www\12321.php on line 20

Notice: Undefined index: submit in F:\php\www\12321.php on line 20

日志里面也不会记录错误，页面里面也不会报错

谢谢你们的帮助，$_POST改成$_REQUEST和$_GET, $c=$_REQUEST[“submit”];还是会提示一下错误

otice: Undefined index: fname in F:\php\www\12321.php on line 18

Notice: Undefined index: age in F:\php\www\12321.php on line 19

Notice: Undefined index: submit in F:\php\www\12321.php on line 20

错误的这几行内容
$a=$_GET["fname"];
$b=$_GET["age"];
$c=$_REQUEST[“submit”];

 $a=$_GET["fname"];
$b=$_GET["age"];
$c=$_POST[submit];

第三行是什么鬼？你表单上明明写的get方式啊。要么用$_GET,要么用$_REQUEST。为什么要用$_POST呢？

还有submit提交之后触发的是一个提交动作，本身并没有特定的值的。

notice 是一个提示不是错误是因为你在没有提交的时候获取不到值提示的错误还有你为什么要给submit一个name 啊？

谢谢你们的帮助，$_POST改成$_REQUEST和$_GET, $c=$_REQUEST[“submit”];还是会提示一下错误

otice: Undefined index: fname in F:\php\www\12321.php on line 18

Notice: Undefined index: age in F:\php\www\12321.php on line 19

Notice: Undefined index: submit in F:\php\www\12321.php on line 20

错误的这几行内容
$a=$_GET["fname"];
$b=$_GET["age"];
$c=$_REQUEST[“submit”];

为什么不用post提交呢？试试