判断form提交的是数字还是字符串
<!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>
<style type="text/css">
<!--
body,td,th {
font-size: 12px;
}
body {
margin-left: 20px;
margin-top: 20px;
}
-->
</style>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>判断字符串</title>
</head>
<body>
<table border="0" align="center" cellpadding="0" cellspacing="0">
<form method="post" aciton="#">
<tr>
<td height="25">请输入25位数字：</td>
<td><input type="text" name="text" maxlength="30" size="28"></td>
<td><input type="submit" name="submit" value="检测"></td>
</tr>
<tr>
<td colspan="3" height="25" align="center" valign="middle">
<?php
if(isset($_POST['submit'])){
if(isset($_POST['text']) && $_POST['text'] != ''){
$number = $_POST['text'];
if(is_numeric($number) and strlen($number) <= 25)
echo '输入正确，输入的数字列是：'.$number;
else
echo '输入错误';
}else{
echo '输入不允许为空';
}
}
?>
</td>
</tr>
</form>
</table>
</body>
</html>
