<form method="post" action="" id="myform">

<input type="button" value="submit">

</form>

<script type="text/javascript">

function init(){

    var submitBtn=document.querySelector("input[value=submit]");

    submitBtn.addEventListener("click",function(){

        var form=document.getElementById("myform");

        alert(form.id);

        form.submit();

    })

}

init();

</script>