Slide Up/Down with JQuery until a certain height - is this possible?

Something like this may work:

$("#div").toggle(
function(){
   $("#div").animate( { height:"500px" }, { queue:false, duration:500 });
},
function(){
   $("#div").animate( { height:"50px" }, { queue:false, duration:500 });
});

Instead of the 500px it can just be the original size of the div, and the 30px can be however much you want to show when it's meant to be hidden.

Update from the comments

Here's a fiddle showing that it can allow different heights if declared in a variable. And fading out after animation shouldn't be a problem.

http://jsfiddle.net/Skooljester/HdQSX/

var divTest = $("#test").height();
$("#test").toggle(
function(){
   $("#test").animate({ height: divTest + 'px' }, { queue: false, duration: 500 });
},
function(){
   $("#test").animate({ height:'50px' }, { queue: false, duration: 500 });
});

#test {
  display: block;
  background: #FF0000;
  height: 500px;
  width: 300px;
}

<div id="test">Test</div>

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>

The better way to open div to its original height is using slideDown(). The problem is that this function requires div to be hidden before it can open it. The following way is a little bit ugly but works well:

$("#test").toggle(
function(){
   $("#test").css('height', 'auto').hide().slideDown('fast');
},
function(){
   $("#test").animate( { height:'50px' }, { queue:false, duration:500 });
});

I don't recommend using jQuery's animate method because it's sometimes buggy in some browsers. Animate the slide with CSS transitions is a better choice (according to me), by setting the div height or max-height.

CSS:

.expandable {
  max-height: 3em;
  overflow: hidden;
  transition: max-height .3s;
}

on click, set max-height with jQuery:

$(.someSelector).css('max-height', expandedHeight);

Then remove the styling when it's clicked again:

$(.someSelector).attr('style', '');

You can look at this demo example