js中的打印

function doPrint() {
             bdhtml=window.document.body.innerHTML;
             sprnstr="<!--startprint-->";
             eprnstr="<!--endprint-->";
             prnhtml=bdhtml.substr(bdhtml.indexOf(sprnstr)+17);
             prnhtml=prnhtml.substring(0,prnhtml.indexOf(eprnstr));
             window.document.body.innerHTML=prnhtml;
             window.print();
          }

在需要打印的内容前面加上这对:<!--startprint-->与<!--endprint-->