<script>
  navHeight = $('#main_navigation').height();
  //ナビ部分の高さ計測用

  $(window).on('load', function() {
    var url = $(location).attr('href');
    setTimeout(function(){
        if(url.indexOf("?id=") != -1){
            var id = url.split("?id=");
            var $target = $('#' + id[id.length - 1]);
            if($target.length){
                var pos = $target.offset().top;
                var target_top = pos - navHeight;//ここでナビの高さを引く
                $("html, body").animate({scrollTop:target_top}, 1500);
            }
        }
    },100);
  });
</script>