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 >
$(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>