Form in a colorbox popup won't submit

Question

I've got a form which pop-ups on click to edit the selected item.

When I hit submit it just reloads the page and nothing else happens.

I've tried so many approaches but no luck so far.

So this is my html:

<ul>
    <li>
        <div class="cust_row_10"><a href="item_info.php?id=3" title="Click to view the item" class="itemPopup">item 3</a></div>
    </li>
    <li>
        <div class="cust_row_10"><a href="item_info.php?id=4" title="Click to view the item" class="itemPopup">item 4</a></div>
    </li>
</ul>

and JavaScript:

$(document).ready(function() {
    $('.itemPopup').colorbox({ transition:'none', width:'90%', height:'90%'});
});