a 锚点跳转滑动效果

点击a链接时，跳转到相应id的位置处，有一个滑动效果。

<a href="#my">我是跳转到div</a>
<div id="my"></div>
<script>
$(function(){
    //锚点跳转滑动效果
    $('a[href*=#],area[href*=#]').click(function() {
        console.log(this.pathname)
        if (location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '') && location.hostname == this.hostname) {
            var $target = $(this.hash);
            $target = $target.length && $target || $('[name=' + this.hash.slice(1) + ']');
            if ($target.length) {
                var targetOffset = $target.offset().top-50;
                $('html,body').animate({
                            scrollTop: targetOffset
                        },
                        1000);
                return false;
            }
        }
    });
})
</script>