For illustration: http://jsfiddle.net/skyrim/j2RWt/4
Give this a try:
var $content = $("#left");
var offset = $content.offset();
$("<div></div>").css({
width: 0,
position: "absolute",
left: offset.left,
top: offset.top,
height: $content.outerHeight(),
backgroundColor: "White"
}).appendTo("body")
.animate({
width: $content.outerWidth()
}, 1000, function () {
$content.css('visibility', 'hidden');
$(this).remove();
});
UPDATE
After understanding the actual requirement (:p), this technique essentially overlays another div on top of the initial element. I have tested it in IE and will provide further updates after testing in other browsers!
UPDATE
Chrome appears to be the only browser facing difficulties in determining the correct height.
Implemented a callback that hides visibility (as recommended by LEOPiC) and removes the overlaying div afterwards