Javascript - get element (button) without ID or Class?

Possible Duplicate:
Get list of all input objects using JavaScript, without accessing a form object

How can I get elements, like all buttons on a page, without class or ID?

Is there anything like this?

document.getElementsByType(button)

EDIT

My confusion was how to get all buttons (not just one) without class or ID.

the solution ended up being

    var buttons = document.getElementsByTagName('button');

for (var i = 0, len = buttons.length; i < len; ++i) {

but your answer is what led me to find out what I didn't know to ask in the first place... So, thanks everyone!