[jQuery] Multiple checkbox validation

[OOps]

<div>
        <ul id="sortable">
            <li id="1"><span></span>
                Item1
                <input type="checkbox" id="chk1" value="1" /><img
src="images/close.gif"
                    onclick="ClearSearchDataOnClose1()" />
            </li>
            <li id="2"><span></span>
                Item 2
                <input type="checkbox" id="Checkbox1" value="2" /><img
src="images/close.gif"
                    onclick="ClearSearchDataOnClose2()" /></li>
            <li id="3"><span></span>
                Item 3<input type="checkbox" id="Checkbox2" value="3" /
><img src="images/close.gif"
                    onclick="ClearSearchDataOnClose3()" /></li>
            <li id="4"><span></span>
                Item 4<input type="checkbox" id="Checkbox3" value="4" /
><img src="images/close.gif"
                    onclick="ClearSearchDataOnClose4()" /></li>
            <li id="5"><span></span>
                Item 5<input type="checkbox" id="Checkbox4" value="5" /
><img src="images/close.gif"
                    onclick="ClearSearchDataOnClose5()" /></li>
            <li id="6"><span></span>
                Item 6<input type="checkbox" id="Checkbox5" value="6" /
><img src="images/close.gif"
                    onclick="ClearSearchDataOnClose6()" /></li>
            <li id="7"><span></span>
                Item 7<input type="checkbox" id="Checkbox6" value="7" /
><img src="images/close.gif"
                    onclick="ClearSearchDataOnClose7()" /></li>
        </ul>
    </div>



I need to validate the checkbox given above... My requirement is only
one check box is checked at a time on button submit... If more than
one check box is checked i want to show the alert message. i want to
validate the checkbox using jquery....