Jquery scroll anchor up

So I am using the following script to scroll named anchors smoothly, but it doesn't work when the destination is above the anchor in the page (won't scroll upwards).

    $(document).ready(function(){
      $('a[href^="#"]:not(.top)').click(function(event){
        event.preventDefault();
    var full_url = this.href;
        var parts = full_url.split("#");
        var trgt = parts[1];
        var target_offset = $("#"+trgt).offset();
        var 开发者_Go百科target_top = target_offset.top;
        $('html, body').animate({scrollTop:target_top}, 500);
    });
});

Does anyone know how to make it up friendly?

Edit:

I am currently using this to scroll upwards now, but if you know of a cleaner way to do it in one function please post away:

  $('.top').click(function(event){
    event.preventDefault();
    $('html, body').animate({scrollTop:0}, 500);
});

---

It works for me, using element IDs instead of named anchors.

You should be using IDs instead of named anchors anyway - named anchors are deprecated in HTML5. That is:

<a name="section1"><h1>Section One</h1></a>

should be:

<h1 id="section1">Section One</h1>

And you can combine the scrolling in one function:

$('a[href^="#"]').live('click',function(event){
    event.preventDefault();
    var target_offset = $(this.hash).offset() ? $(this.hash).offset().top : 0;
    $('html, body').animate({scrollTop:target_offset}, 500);
});