DBJ isFunction()

dbj.isfunction.js

/* 
(c) 2009 - 2011 by dbj.org 
 */
    var isFunction = (function() {
        var rx = /^\s*\bfunction\b/;
        return function(f) {
                return rx.test(f);
        }
    }());
/* 
Anti Jokers version, who think it is awesome
to abuse code with calls like this: 

isFunction("function");

(c) 2009 - 2011 by dbj.org 
 */
var isFunction4jokers = (function() {
    var rx = /^\s*\bfunction\b/;
    return function(f) {
        return "function" === typeof f ? true : "object" === typeof f ?
        rx.test(f) : false;
    }
}());