用同一个form表单实现登陆和注册
<html>
<head>
<script language = "JavaScript">
function login(){
document.forms[0].action = "http://www.sina.com";
document.forms[0].submit();
}
function register(){
var username = document.getElementsByName("username")[0].value;
alert(username);
}
</script
</head>
<body>
<form name = "user" >
用户名<input type = "text" name = "username"><br/>
密码 <input type = "password" name = "password"><br/>
<input type = "button" onclick = "login()" value = "登录">
<input type = "button" onclick = " register()" value = "注册">
</form
</body>
</html>