HTML5 history pushState is not working

Question

Not sure what I'm doing wrong, but this small bit of code does not work:

window.history.pushState("foo", "foo", "foo");

It will generate the following error in firefox 29:

TypeError: window.history.pushState is not a function

Answer 1

Apparently one of the scripts I included had a declaration:

var history = ...;

Unbeknownst to me, all vars on the root actually live in the window scope so the custom history var actually overwrote the original window.history.