Fixes IE10's broken path

window_location_path.js

// After some brainstorming with coworker Ara Pehlivanian,
// we came up with this monkey-patch for IE10, to help it
// normalize pathname to work like all other browsers.
//
// This forces path to be equal to "/foo/bar" regardless
// of what window.location.pathname actually resolves to:
//
// -- "/foo/bar" = Correct in all other browsers.
// -- "foo/bar"  = Incorrect in IE10.

var path = ('/' + window.location.pathname).replace('//', '/');

Seems a bit inefficient to prefix pathname and then undo that again in every browser besides IE10. How about this:

var path = window.location.pathname;
if (path[0] !== '/') {
path = '/' + path;
}

See comparison here: http://jsperf.com/replace-vs-rewrite

If I were reassigning the variable in a loop, I'd definitely speed-optimize it.