window.Print()打印功能，火狐正常，IE浏览器中css样式无效

代码：

function Print() {
                document.getElementById("btnPrint").style.display="none";
                bdhtml = window.document.body.innerHTML;
                sprnstr = "<!--startprint-->";
                eprnstr = "<!--endprint-->";
                prnhtml = bdhtml.substr(bdhtml.lastIndexOf(sprnstr));
                prnhtml = prnhtml.substring(0, prnhtml.lastIndexOf(eprnstr));
                window.document.body.innerHTML = prnhtml;
                window.print();
            }