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:高一英语听力(牛津译林版必修3) 下一篇:高二英语听力(牛津译林版必修5) '; }