JavaScript页面中的打印功能

<script type="text/javascript">
 function preview(oper) {

            if (oper < 10) {
                bdhtml = window.document.body.innerHTML; //获取当前页的html代码
                sprnstr = "<!--startprint" + oper + "-->"; //设置打印开始区域
                eprnstr = "<!--endprint" + oper + "-->"; //设置打印结束区域
                prnhtml = bdhtml.substring(bdhtml.indexOf(sprnstr) + 18); //从开始代码向后取html
                prnhtml = prnhtml.substring(0, prnhtml.indexOf(eprnstr)); //从结束代码向前取html
                window.document.body.innerHTML = prnhtml;
                window.print();
                window.document.body.innerHTML = bdhtml;
            } else {
                window.print();
            }
        }
    </script>

 <!--startprint1-->
 <table width="100%"  cellspacing="2" cellpadding="2">
<tr>

<td>2</td>

<td>3</td>

<td>4</td>

<td>5</td>

</tr>

<tr>
<td>2</td>

<td>3</td>

<td>4</td>

<td>5</td>

</tr>

<tr>
<td>2</td>

<td>3</td>

<td>4</td>

<td>5</td>

</tr>
</table>
 <!--endprint1-->

 <input class="button"  onmouseover="this.className='buttonover'" onmouseout="this.className='button'" type="button" value="打 印" onclick="preview(1)" />