getting value from nested function
<p>I just can not get the value of arr. Any suggestion...</p>

<pre><code>function my_f() {
    var arr;
    $.post('data.php', function(data) {
        arr = $.makeArray($("tr",data).map(function(){
            return $(this).attr("id");
        }).get());

        return false;
        //alert(arr); ...this work 
    });
    return arr;
}

alert(my_f()); //return undefined
</code></pre>
