jQuery Animate 1.6

Backward compatibility without using units (px)

HTML

<div class="bttn"></div>

CSS

.bttn{
    width:200px;
    height:200px;
    border:1px solid red;
}

JavaScript

$('div').animate({
    marginLeft: "-200",
    marginTop: "-200",
    width: "400",
    height: "400"
    // Comment the line below to see difference
    ,opacity: 0.5
}, 2000).animate({
    marginLeft: -150,
    marginTop: -150,
    width: 300,
    height: 300
    // Comment the line below to see difference
   ,opacity: 1
}, 2000);