Edit in JSFiddle

/**
* @author Larry Battle, http://bateru.com/news
* @date May 12, 2012
*/
(function (global) {
    var _isNaN = function () {};
    var type = function(val){
        return Object.prototype.toString.call(val);
    };
    var runAllTests = function () {
        test("test for non-numbers.", function () {
            var x = [ undefined, null, [], {}, /regex/, true, false, Math, this, NaN, "string", 0/0    ];
            
            for (var i = 0, len = x.length; i < len; i++) {
                equal(_isNaN(x[i]), true, "Type \'" + type(x[i]) + "\' with value, "+x[i]+", should not be a number.");
            }
        });
        test("test for numbers.", function () {
            var x = ["-10", 16, 0xFF, "0xFF", 8e5, 3.1415, Math.PI, +10, 0144, 0, '0', 42, 1, 1 / 0, -1 / 0, Number(5)];
            
            for (var i = 0, len = x.length; i < len; i++) {
                equal(_isNaN(x[i]), false, "Type \'" + type(x[i]) + "\' with value, "+x[i]+", should not be a number.");
            }
        });
        
        
    };
    var funcs = {
        "withoutFix" : global.isNaN,
        "withFix" : (function () {
            var _isNaN = global.isNaN;
            return function (val) {
                return _isNaN("" + val) || (typeof val === "object" && !(val || "").hasOwnProperty('push'));
            };
        }()),
        "jQueryIsNumeric": function(obj){
            return !isNaN( parseFloat(obj) ) && isFinite( obj );
        }
    };
    var updateFunction = function () {
        var funcName = $(this).attr('id') || 'withFix';
        _isNaN = funcs[funcName];
        QUnit.reset();
        QUnit.init();
        QUnit.start();
        runAllTests();
    };
    $("input[name='isNaNFunction']").click(updateFunction);
    updateFunction();
}(this));
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
                    "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <link rel="stylesheet" href="http://code.jquery.com/qunit/git/qunit.css" type="text/css" media="screen" />
    </head>
    <fieldset>
        <legend>Settings</legend>
        Which version of isNaN would you like to test?<br/>
        <input type="radio" name="isNaNFunction" id="withFix" checked="checked"/><label for="withFix">Fixed Version: </label><br/>
        <input type="radio" name="isNaNFunction" id="withoutFix"/><label for="withoutFix">Browser Native Version: </label> <br/>
        <input type="radio" name="isNaNFunction" id="jQueryIsNumeric"/><label for="withoutFix">jQuery isNumeric Version: </label> 
        <br/>
        More Information at <a href="http://bateru.com/news/">bateru.com/news</a>
    </fieldset>

    <body>
        <h1 id="qunit-header">QUnit example</h1>
        <h2 id="qunit-banner"></h2>
        <div id="qunit-testrunner-toolbar"></div>
        <h2 id="qunit-userAgent"></h2>
        <ol id="qunit-tests"></ol>
        <div id="qunit-fixture">test markup, will be hidden</div>
        <script src="http://code.jquery.com/jquery-latest.js"></script>
        <script type="text/javascript" src="http://code.jquery.com/qunit/git/qunit.js"></script>  
    </body>
</html>?