jQuery attr() not working inside jQuery Validation plugin?! Returns undefined!

Question

So I am using attr("alt") inside the "success" block in jQuery Validation plugin. However, attr("alt") returns undefined even though the attribute ("alt") is definitely defined.

Here's my code:

$(this).validate({
    success: function(label) {
        var api = $('#' + label.attr("for")).qtip("api");
        api.updateContent($('#' + label.attr("for")).attr("alt"), true);
    }
})

So label.attr("for") works just fine and returns the id of the target input field. However, when I plug that in to $('#' + label.attr("for)).attr("alt"), it returns undefined even though the alt attribute is defined. Am I missing something or is this something that happens with the jQuery Validation plugin (maybe it removes the alt attribute on-the-fly without me knowing about it?)

Help is greatly appreciated!!!

EDIT: In fact $('#' + label.attr("for")).attr("id") and attr("name") both work as expected too. So it seems it's specifically attr("alt") that isn't working. Could qTip be doing something funky (since I think it takes alt as default value for tooltip content)?

UPDATE: More baffling yet... $('#' + label.attr("for")).attr("alt") DOES NOT WORK, but $('#' + label.attr("for"))[0].alt DOES WORK. I'm just gonna use that as a solution, but does anyone know WHY???