打印指定内容

function preview(oper) {
    var page = window.document.body.innerHTML;
    bdhtml = window.document.body.innerHTML;//获取当前页的html代码
    sprnstr = "<!--startprint" + 1 + "-->";//设置打印开始区域
    eprnstr = "<!--endprint" + 1 + "-->";//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();
}