document.createElement multiple arguments

I was reading through the polymer documentation, and I saw this:

var el2 = document.createElement('input', 'my-input'); Source

Forgetting about polymer for a second, can document.createElement currently take 2 arguments? Is it related to Polymer's type-extensions?

Side note: Webstorm was "complaining" when I called it with 2 arguments.

Copyright Notice：Content Author:「Alon Amir」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/30767350/document-createelement-multiple-arguments