Animate Height Bottom to Top Instead of Top to Bot

问题:

How can I achieve height animation in reverse?

Instead of the typical animation starting from the top and working its way down, how can I have it start the animation from the bottom of the element and work its way up towards the top of the element?

The event is triggered by a#link-1, the animation takes place in div#line-1.

This is my code: It doesn't appear to be working. :-/

HTML

<div id="pageContainer">
    <div id="line-1"></div>
    <a id="link-1" title="" href="#">Link 1</a>
</div><!-- end #pageContainer -->

CSS

#pageContainer{
    position: relative;
    margin: 0px 0px 200px 0px;
    min-height: 748px;
    height: 748px;
    background: url('../img/sprite.png') bottom center no-repeat;   
}
a#link-1{
    position: absolute;
    top: 686px;
    left: 36px;
    text-align: center;
    display: block;
    width: 76px;
    height: 24px;
    line-height: 24px;
    z-index: 20;
}
div#line-1{
    position: absolute;
    top: 4px;
    left: 30px;
    width: 340px;
    height: 687px;
    background: url('../img/sprite.png') 0px 0px no-repeat; 
}

JS

// Initially hide                      
$("div#line-1").hide();
// Activate Line 1
$('a#link-1').click(function() {
    $('div#line-1').animate({
    opacity: 0.25,
    height: 'toggle'
    }, 5000, function() {
// Animation complete.
    });
});

回答1:

You div and your a tags have the same ID. They must have unique IDs.

$('a#line-1').click(function() {
    $('div#line-1').animate({

needs to be something like:

$('a#line-1').click(function() {
    $('div#unique_id').animate({

Example Fix

回答2:

position: absolute;
bottom: 0px;

animate bottom + 1.

You can also use negative values for top or margin-top to move upwards.

回答3:

Animate as you would for top-to-bottom, but add element.scrollTop = 99999;

This will ensure that the bottom of the content is visible (unless for some reason it's 100,000 pixels tall) and the effect will be bottom-to-top animation.