Greetings, Is there a way for me to get to the parent <form> node from an element node?

<form id="frm1">
<input id="myinput" type="text" value="myval" />
</form>

<script>
var myinput = document.getElementById('myinput');

//can I get a hold of <form id="frm1"> using myinput?
</script>