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:2018版物理(教科版)新课堂同步必修一课件+文档 下一篇:2018版物理(鲁科版)新课堂同步必修一课件+文档 '; }