Can anyone help with this strange form submiting in FireFox?

So this form should be submitted after pushing "go to submit" button. There is an onclick event on the button that should submit form through JavaScript. In the form there is another button "test" without any onclick event. Following the script, the form should be submitted only after pushing the "go to submit" button, but it submits even pushing at "test" button.

In the Internet Explorer it works well! But this stupid FireFox browser behaves different.

Here is example of HTML page:

<script>
function func(){
document.form1.submit();
}
</script>

<form name="form1" method="post" action="somewhere.php">
<button>test</button>
<input type="button" value="go to submit" onclick="func();">
</form>

I have several buttons with <button onclick="...">option 1</button> options. I want to fix strange submiting a form in FireFox. Help please!