James Tauber

journeyman of some

blog > 2008 > 04 > 28 >

Auto-Scrolling in jQuery

I mentioned in my previous post New Site Look that, inspired by 37 Signals, I wanted to auto-scroll pages in my website in two circumstances:

Here's the fragment of my Django template that achieves both of these with jQuery: 

<script type="text/javascript" src="/static/jquery.js"></script>
<script type="text/javascript">
    function scrollTo(selector) {
        var targetOffset = $(selector).offset().top;
        $('html,body').animate({scrollTop: targetOffset}, 500);
    }
    $(document).ready(function() {
        $('#add_comment_toggle').click(function() {
            $('form.add_comment').slideToggle();
            scrollTo('form.add_comment');
            return false;
        });
        {% if comment_error %}
        $('form.add_comment').show();
        scrollTo('.comment_error');
        {% endif %}
    });
</script>

The only bit of Django, for those who don't know it, is the {% if ... %} which only includes that Javascript if a comment_error exists.

The scrollTo function scrolls to the element whose selector is given. Notice how, if a comment_error exists, I make sure the form is showing first, then call scrollTo.

Also, in my code for toggling the Add Comment form, I call the function to scroll to the form.

Categories:
prev « django » next
prev « web_design » next
prev « javascript
jquery

Comments (6)

Simon Willison on April 28, 2008:

You can neatly package your scrollTo function up as a jQuery plugin:

jQuery.fn.autoscroll = function(selector) {
$('html,body').animate(
{scrollTop: $(selector).offset().top},
500
);
}

Then to scroll to the comment error field do this:

$('.comment_error').autoscroll();

James Tauber on April 29, 2008:

Thanks Simon. Didn't know how to do that but now I do :-)

Aidas Bendoraitis on April 29, 2008:

I would rather change the Django-template-based condition to a Javascript-based condition. Then you could move all the Javascript code into a separate file:

if ($('.comment_error').length) {
$('form.add_comment').show();
scrollTo('.comment_error');
}

James Tauber on April 29, 2008:

Good point, Aidas.

Aidas Bendoraitis on May 6, 2008:

The way proposed by Simon Willison doesn't work at least with jQuery 1.2.2. The correct code for jQuery plugin is this:

{{{

(function($){
$.fn.autoscroll = function() {
jQuery('html,body').animate(
{
scrollLeft: this.offset().left,
scrollTop: this.offset().top
},
500
);
return this;
};
})(jQuery);

}}}

adam j. sontag on May 8, 2008:

ariel flesler's jQuery.scrollTo plugin...

http://flesler.blogspot.com/2007/10/jqueryscrollto.html

Add a Comment

Created: April 28, 2008
Last Modified: April 28, 2008
Author: jtauber