追記2

document.body.innerHTML=document.body.innerHTML.split('---').join('<div class=ad2>---</div>');
var result = document.evaluate('//div[@class="ad2"][1]/following-sibling::text()',document, null, 7, null);
for(var i=0;i<result.snapshotLength;i++)
	{
  		result.snapshotItem(i).remove()
        //result.snapshotItem(j).style.display='none';
    }
.ad2{display:none;}
.ad2~*{display:none;}