form表单中写入button按钮的提交

<div>
    <form action="/registe/m" id='verify' method='post'>
        {%csrf_token%}
       <input type="text" id='username' name="username" value=''><br>
       <input type="password"  id='password' name="password" value=''><br>
       <input type='hidden' id='a' name="a">
       <input type='hidden' id='s' name="s">
       <input type='hidden' id='params' name="params">
       <input type="button" onclick="formSubmit()" value="Registe">


    </form>
</div> 




<script>
    
        var a = 'FF';
        var s= 'n';
        var username = document.getElementById('username').value;
        var password = document.getElementById('password').value;
        function formSubmit(){
            document.getElementById('a').value=a;
            document.getElementById('s').value=s;
            document.getElementById('params').value=params;
            document.getElementById('verify').submit();
        }