I'm looking to create something that can move randomly inside of a fixed div container. I love the way the object moves in this example that I found searching this website...

http://jsfiddle.net/Xw29r/15/

The code on the jsfiddle contains the following:

$(document).ready(function(){
animateDiv();

});

function makeNewPosition(){

// Get viewport dimensions (remove the dimension of the div)
var h = $(window).height() - 50;
var w = $(window).width() - 50;

var nh = Math.floor(Math.random() * h);
var nw = Math.floor(Math.random() * w);

return [nh,nw];    

}

function animateDiv(){
var newq = makeNewPosition();
var oldq = $('.a').offset();
var speed = calcSpeed([oldq.top, oldq.left], newq);

$('.a').animate({ top: newq[0], left: newq[1] }, speed, function(){
  animateDiv();        
});

};

function calcSpeed(prev, next) {

var x = Math.abs(prev[1] - next[1]);
var y = Math.abs(prev[0] - next[0]);

var greatest = x > y ? x : y;

var speedModifier = 0.1;

var speed = Math.ceil(greatest/speedModifier);

return speed;

}?

CSS:

div.a {
width: 50px;
height:50px;
background-color:red;
position:fixed;

}?

However, I don't believe the code above constricts that object at all. I need my object to move randomly inside of a container that is let's say for now... 1200px in width and 500px in height.

Can someone steer me in the right direction? I'm super new to coding so I'm having a hard time finding an answer on my own.

Thanks so much!

James