Javascript throws an "is undefined" error
<p>I've been working with Javascript and recently I've been stucked with an error which I can't solve.</p>

<p>The Firefox console throws an "info[last] is undefined" error, and I've got no idea what is causing that. Here is the code, the line which provokes the trouble is number 7:</p>

<pre><code>$("textarea").each(function() {
var id = $(this).parents("div.article").attr('id').split('_')[1],
    kind = $(this).attr("class"),
    text = $(this).val(),
    last = info.length-1;

    if(last !== 0) {

        if(info[last].id == id) {
            info[last].info.push([kind, text]);

        }

    } else {

        object = {
            id: id,
            info: [[kind, text]]
        };

    }

    info.push(object);
});
</code></pre>

<p>Hope you guys can help me figure it out.</p>
