Browser detection script v3.0

annotated.js

/*
({}).toString.call()
[object global]    // chrome < 13 in 14 - [object Undefined] :(
[object Undefined] // ff
[object Window]    // opera
[object DOMWindow] // safari
[object Object]    // ie
*/
function (a) {
    // undefined magic
    a = {}.toString.call()[8];

    return {
        f: a == 'U', // is Firefox?
        o: a == 'W', // is Opera?
        s: a == 'D', // is Safari?
        c: a == 'g', // is Chrome?
        i: !a || a == 'O'  // is IE?
    }
}

index.js

// 93 byte length
function(a){a={}.toString.call()[8];return{f:a=='U',o:a=='W',s:a=='D',c:a=='g',i:!a||a=='O'}}
/* alternative 77 byte length
function(){return{U:'f',W:'o',D:'s',g:'c',O:'i'}[{}.toString.call()[8]]||'i'}
*/

LICENSE.txt

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 azproduction

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

package.json

{
  "name": "browser",
  "description": "Browser detection script",
  "keywords": [
    "browser",
    "detect",
    "detection",
    "firefox",
    "opera",
    "safari",
    "chrome",
    "ie"  
  ]
}

test.html

<pre id="br"></pre>
<script>
var b = function(a){a={}.toString.call()[8];return{f:a=='U',o:a=='W',s:a=='D',c:a=='g',i:!a||a=='O'}}();
document.getElementById('br').innerHTML = b.f && 'Firefox' || 
                                          b.o && 'Opera'   || 
                                          b.s && 'Safari'  || 
                                          b.c && 'Chrome'  || 
                                          b.i && 'Ie'      || 
                                                 '???'     ;
</script>

<!-- Alt version -->
<pre id="br2"></pre>
<script>
var b = function(){return{U:'f',W:'o',D:'s',g:'c',O:'i'}[{}.toString.call()[8]]||'i'}();
document.getElementById('br2').innerHTML = {f:'Firefox',o:'Opera',s:'Safari',c:'Chrome',i:'IE'}[b];
</script>

An awesome detection!
But my Chrome 14 shows [object Undefined] as Firefox.

I can just pass undefined to call() and ill get the same. ({}).toString.call() same as ({}).toString.call(void 0). this.prototype is undefined aswell... :)
@tsaniel sad that it was fixed

One more thing, IE7 doesn't support array-like string.

yep i use fallback !a||a=='O'