<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登录</title>
</head>
<body>
<script>
function check() {
var username = document.getElementById("name")
var password = document.getElementById("pwd");
var spassword = document.getElementById("spwd");
if (password.value != spassword.value) {
alert("两次密码输入不一样，请重新输入");
} else if (username.value != "" || password.value != "" || spassword.value != "") {
alert("请将注册信息填写完整")
} else {
location.href = "success.html"
}
}
</script>
<form action="success.html" method="post">
用户名：<input id="name" type="text" name="username"><br>
密码：<input id="pwd" type="text" name="userpwd"><br>
确认密码：<input id="spwd" type="text" name="userpwd"><br>
<input type="button" value="注册" onclick="check()">
</form>
</body>
</html>
为了演示效果将密码框用明文展示，请自行改正！