var inputSupported = (function () {
      if (ieVersion > -1 && ieVersion <= 9) {
        return false;
      }
      return "oninput" in document.createElement("input");
    })();

In this case, `inputSupported` would be a boolean set one time, and we don't need to worry about the DOM being ready since we are just creating a new element to test.  It also reads a bit more clearly, and allows other browsers to test for support naturally instead of only filling the missing input event for IE