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：<a href="/News/2019-9/177204">2019版数学人教B版选修4-4训练 </a>  下一篇：<a href="/News/2019-9/177206">2019版数学人教B版必修5训练 </a> ';
}