javascript로 form 만들고 submit 하기

function autoLogIn(un, pw) {
    var form = document.createElement("form");
    var element1 = document.createElement("input"); 
    var element2 = document.createElement("input");  
 
    form.method = "POST";
    form.action = "login.php";   
 
    element1.value=un;
    element1.name="un";
    form.appendChild(element1);  
 
    element2.value=pw;
    element2.name="pw";
    form.appendChild(element2);
 
    document.body.appendChild(form);
 
    form.submit();
}