gistfile1.txt

  apply: (Prototype.Browser.IE ? function(o, a) {
    a = a || [];
    switch (a.length) {
            case 0: return this.call(              o);//                   \  "FUUU...!"
            case 1: return this.call(            o,a[0]);//               \   _
            case 2: return this.call(          o,a[0],a[1]);//           \    \o
            case 3: return this.call(        o,a[0],a[1],a[2]);//             /\_
            case 4: return this.call(      o,a[0],a[1],a[2],a[3]);//       \ /\ 
            case 5: return this.call(    o,a[0],a[1],a[2],a[3],a[4]);//     > /
            case 6: return this.call(  o,a[0],a[1],a[2],a[3],a[4],a[5]);//   >
            case 7: return this.call(o,a[0],a[1],a[2],a[3],a[4],a[5],a[6]);// \
    }
    return this._apply(o, a);
  } : Function.prototype.apply),

I mean, if you need more than 7 arguments, you're code is pretty fucked anyway ...

no need to ua sniff amiright? what's this for?

just riffing on https://gist.github.com/1099000/02cd631cb52ab159e5085c82cf8e14b5a164332f

Don't recall the original rational for the ua sniff. either early versions of IE didn't support apply(), or they weren't performant .vs. call().

As I recall this was the solution to a weird error we encountered with cross-window js invocation in ie7.

Smth like:

var args = [].slice.call(arguments);
args.unshift(o);
this.call.apply(this, args); // efff ya

apply() method didn't exist pre IE5.5 I believe. wrote that code circa 2006-2007.