function chkdiv(divid){ var chkid=document.getElementById(divid); if(chkid != null){return true; } else {return false; } } if (chkdiv('fy')){ document.getElementById('fy').innerHTML='上一篇:2013步步高生物一轮复习配套课件:遗传变异 下一篇:2013届高三英语暑假单选强化训练(9份) '; }