<script type="text/javascript">
document.getElementById("username").value;
</script>
</head>
<body>
<form action="">
用户名:
<input type="text" name="username" id="username" /><br> </form>为啥显示我缺少对象呢?
document.getElementById("username").value;
</script>
</head>
<body>
<form action="">
用户名:
<input type="text" name="username" id="username" /><br> </form>为啥显示我缺少对象呢?
把你全部的html贴出来 。
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
document.getElementById("username").value;
</script>
</head>
<body>
<form action="">
用户名:
<input type="text" name="username" id="username" /><br>
密码:
<input type="password" name="pass" /><br>
确认密码:
<input type="password" name="re-pass" /><br>
年龄:
<input name="age" /><br>
出生日期:
<input name="bod" /><br>
<button onclick=" validationUserName();">提交</button>
</form>
</body>
</html>
<script type="text/javascript">
window.onload=function(){
document.getElementById("username").value;
}
</script>或者把JS移到文件的尾部去