<!DOCTYPE html>
<head>
<meta charset="UTF-8">
<title>注册功能(表单校验)</title>
<script type="text/javascript">
function check(){
alert("check");
var username = document.getElementById("username");
console.log(username);
console.log(username.value);
return false;
}
</script>
</head>
<body>
<form action="register.jsp" onsubmit="return check()">
<table border="1" width="500px" height="500px">
<tr>
<td colspan="2" align="center">注册</td>
</tr>
<tr>
<td align="right">用户名:</td><td align="left"><input type="text" id="username" /></td>
</tr>
<tr>
<td align="right">邮箱:</td><td><input type="text" /></td>
</tr>
<tr>
<td align="right">密码:</td><td><input type="password" /></td>
</tr>
<tr>
<td align="right">重复密码:</td><td><input type="password" /></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="注册"/></td>
</tr>
</table>
</form>
</body>
</html>
1,怎么通过id获得某个元素
document.getElementById("idname")
2,怎么获得输入框输入的内容
ele.value
3,怎么修改元素的内容
ele.innerHTML
4,两种给出用户提示的方式
alert方式
网页上显示
5,校验的时机
onsubmit
onchange
onfocus onblur