var o = document.querySelectorAll("#anqu");
for (var i = 0; i < o.length; i++)
{
    o[i].innerHTML = o[i].innerHTML.replace(/gaosudu/g,"tuicha");
}

$("div [id=anqu]").each(function(){       
    console.log(2);  
    $(this).html().replace(/gaosudu/g,"tuicha");   
});