[JavaScript] 특정 영역의 레이어만 인쇄하기

<script>
    var initBody;
    function beforePrint()
    {
        initBody = document.body.innerHTML;
        document.body.innerHTML = div_page.innerHTML;
    }
    function afterPrint()
    {
        document.body.innerHTML = initBody;
    }
    function pageprint()
    {
        window.onbeforeprint = beforePrint;
        window.onafterprint = afterPrint;
        window.print();
    }
</script>

<a href="#" onclick="pageprint()"> 인쇄하기</a>
<div id="div_page">여기만 인쇄</div>