求大神看看一个超简单的网页代码

为什么这个我点击注册后没有效果呢？

 <!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content = "text;html;charset=gbk">
<title>注册</title>
<script  language="javascript" type="">
    function LoginSubmit(){
        var name = document.Sign.name.value;
        var password = document.Sign.password.value;
        var enpass = document.Sign.Ensurepassword.value;
        if(name==null||name==""||password==null||password==""||enpass==null||enpass==""){
            alter("用户名或密码或确认密码不能为空!");
        }
        else if(password==enpass){
            alter("两次输入密码不一致请重新输入！");
        } else{
            document.Sign.submit();
        }
    }
</script>
<style type="text/css">
body{
background-image:url(ba.jpg); }
</style>

</head>

<body>
<form  method ="POST" name ="Sign" action="SignIn">
<p align = "left">用&nbsp;户&nbsp;名(必填):
<input type="text" name ="name" value="" size="20"></p>
<p allign = "left">密&nbsp;&nbsp;码(必填):
<input type="password" name="password" value="" size="20"></p>
<p align = "left">确认密码(必填):
<input type="password" name="Ensurepassword" value="" size="20"></p>
<p align = "left">性&nbsp;&nbsp;别&nbsp;:&nbsp;
<input type="text" name="sex" value="" size="20"></p>
<p align = "left">性&nbsp;&nbsp;别&nbsp;:&nbsp;
<input type="text" name="sex" value="" size="20"></p>
<p align = "left">住&nbsp;&nbsp;址&nbsp;:&nbsp;
<input type="text" name="address" value="" size="20"></p>
<p align = "left">联系电话:
<input type="text" name="tel" value="" size="20"></p>
<p align="left">
<input type="button" value="注册" name="sure" onclick="LoginSubmit()">
<input type="reset" value="重置" name="reset" >
</p>
</form>
</body>
</html>

alert你拼写错了。

if(name==null||name==""||password==null||password==""||enpass==null||enpass==""){
alert("用户名或密码或确认密码不能为空!");
}
else if(password==enpass){
alert("两次输入密码不一致请重新输入！");
} else{
document.Sign.submit();
}

alter是sql的alert是js弹窗输出

alert 弹出窗口单词写错了

哈哈哈小傻瓜细心一点 alert 单词写错了