Zoom a CSS Circle

HTML

<div id="zoom"></div>

CSS

#zoom {
    width: 50px;
    height:50px;
    border-radius: 75px;
    cursor:pointer;
    background-color: red;
    text-align: center;
}

JavaScript

$('#zoom').hover(
	function() {
		$(this).animate({
			borderTopLeftRadius: 100, 
	    	borderTopRightRadius: 100, 
	    	borderBottomLeftRadius: 100, 
	    	borderBottomRightRadius: 100,
			width: 200,
			height: 200
		}, 500)
	},
	function() {
		$(this).animate({
			borderTopLeftRadius: 75, 
	    	borderTopRightRadius: 75, 
	    	borderBottomLeftRadius: 75, 
	    	borderBottomRightRadius: 75,
			width: 1280,
			height: 780,
		}, 500)
	}
);