<!DOCTYPE html>
<html>
<body>
<form id="formid">
<button id="buttonid" name="abcdefg" type="submit" value="Button Value">The Button</button>
</form>
<br />
<button onclick="GetButtonValue()">Get Form ID</button>
<p id="pid"></p>
<script>
function GetButtonValue() {
var val = document.getElementById("buttonid").form.id;
document.getElementById("pid").innerHTML = val;
}
</script>
</body>
</html>