css div旋转之后自适应

css:
.rotate90deg {
    transform: rotate(90deg);
    -ms-transform: rotate(90deg); /* IE 9 */
    -moz-transform: rotate(90deg); /* Firefox */
    -webkit-transform: rotate(90deg); /* Safari 和 Chrome */
    -o-transform: rotate(90deg); /* Opera */
}

js:

  $("#div").css({
            "width": document.body.clientHeight,
            "height": document.body.clientWidth,
            "position": "absolute",
            "top": ((document.body.clientHeight - document.body.clientWidth) / ),
            "left": -((document.body.clientHeight - document.body.clientWidth) / )
        });