js页面打印

<!--startprint-->
    <div id="content" >打印内容</div>

<!--endprint-->

<button type="button"  onclick="doPrint()">打印</button>

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(); 
         window.document.body.innerHTML=bdhtml;//重新给页面内容赋值；
         return false;
    }