According to [Element.getAttribute](http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-666EE0F9) , it is not guaranteed that getAttribute will return a falsy value if the attribute doesn't exist.
In prepareForDraw the template has already replaced the original element so you don't need to handle the possibility of having a [input type number default step attribute](http://www.w3.org/TR/html-markup/input.number.html#input.number.attrs.step.float) but the value could be "".