<form id="form1" name="form1" method="post">
...
</form>

function f(){
    document.form1.method="post";
    document.form1.submit();
}

I've tried these methods, but all failed:

1.

change method f:

    document.form1.method="post";
    document.form1.submit(function(e) {
        e.preventDefault();
    });

failed.

2.

change form element:

<form id="form1" name="form1" method="post" onclick="return false" onsubmit="return false">
...
</from>

failed.

Is there any way to prevent submitting refreshing the page where the form is?

Thanks a lot.