为什么会出现警告未定义属性值
为什么我写时候placeholder和required会出现警告未定义属性值啊,下面的的input也有,但运行有没有错
为什么我写时候placeholder和required会出现警告未定义属性值啊,下面的的input也有,但运行有没有错
2016-12-06
<!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" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
<title>Document</title>
</head>
<body>
<h2>添加用户</h2>
<form action = "doAction.php?act = addUser" method = "post">
<table border = "1" cellpadding = "0" cellspacing = "0" width = "80%" bgcolor = "#ABCDEF">
<tr>
<td>用户名</td>
<td><input type="text" name="username" id="" placeholder='请输入合法用户名' required='required'/></td>
</tr>
<tr>
<td>密码</td>
<td><input type="password" name="password" id="" placeholder='请输入密码' required='required'/></td>
</tr>
<tr>
<td>年龄</td>
<td><input type="number" name="age" id="" min='1' max='125' placeholder='请输入合法年龄' required='required'/></td>
</tr>
<tr>
<td colspan = '2'><input type = "submit" value = "添加用户"/></td>
</tr>
</table>
</form>
</body>
</html>
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