Making a Chess Game with jQuery UI. I have used Draggable, but i need to make them not stack

http://stackoverflow.com/questions/9770935/making-a-chess-game-with-jquery-ui-i-have-used-draggable-but-i-need-to-make-th/10338542#10338542

by Michael Lajlev

HTML

<table id="chess">
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td><a class="acceptable">&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
            <td><a>&#9817;<a></td>
                
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td></td>
            <td></td>
    ...

CSS

#chess {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    cursor:pointer;
}    
td {
    width: 40px;
    height: 40px;
}
a {
    font-weigt: 600;
    font-size: 30px;
    color: white;
    text-shadow: black 1px 1px 2px;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}
tr:nth-child(odd) td:nth-child(even), tr:nth-child(even) td:nth-child(odd) {
    background-color: grey;
}
tr:nth-child(odd) td:nth-child(odd), tr:nth-child(even) td:nth-child(even){
    background-color: #CCC;
}

JavaScript

$('a').draggable({ containment: "table", revert: 'invalid' });

$('td').droppable({
    drop: function(ev, ui) {
        var dropped = ui.draggable;
        var droppedOn = $(this);
        $(droppedOn).droppable("disable");
        $(dropped).parent().droppable("enable");
        $(dropped).detach().css({top: 0, left: 0}).appendTo(droppedOn);
    }
});   

$('td').not('td:empty').droppable("disable");