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:【优选整合】高中英语人教版必修3(Unit 1) 下一篇:【优选整合】高中英语人教版必修3(Unit 3) '; }