Toggle Inputs Display Based on Checkbox

HTML

<tr>
    <td class="white"><strong>Delivery Address</strong>
    </td>
    <td>Tick
        <input Type="checkbox" id="deliver_same" value="yes"  onClick="checkDeliverSame()" />If delivery address is billing address</td>
</tr>
<div id="delAddress">
    <tr>
        <td>Address line 1</td>
        <td>
            <input class="text" name="saddr1" value="" />
        </td>
    </tr>...
    <tr>
        <td>Post /Zip Code</td>
        <td>
            <input class="text" name="spostalcode" value="" />
        </td>
    </tr>
</div>

JavaScript

function getItem(id) {
    var itm = false;
    if (document.getElementById) itm = document.getElementById(id);
    else if (document.all) itm = document.all[id];
    else if (document.layers) itm = document.layers[id];
    return itm;
}

function checkDeliverSame() {
    var deliverSame = getItem('deliver_same');
    var deliveryAddress = getItem('delAddress');
    if (deliverSame.checked) {
        deliveryAddress.style.display = 'none';
    } else {
        deliveryAddress.style.display = 'block';
    }
}
checkDeliverSame();