實現了鼠標跟隨物體轉動的效果：MouseFollower.js

MouseFollower.js 實現了鼠標跟隨的物體轉動效果，類似 Linux 下的大眼睛。

MouseFollower = (function(){
    var store = [],         //contains an object with an element & invert property
        xdeg = ydeg = 0,    //the current rotationAngles of the cube that is currently being handled
        sPos = {},          //relative pos on screen, seen from the document
        invert = 1;         //look to the mouse cursor or away from it

    document.body.onmousemove = followElements;

    /* helper functions*/
    function prefixStyle(el,p,style){
        var prefixes = ["webkit","moz","o",""],
                i = 0;
        p = p.charAt(0).toUpperCase() + p.slice(1);
        [].forEach.call(prefixes, function(prefix){
            if( prefix == ""){
                p = p.charAt(0).toLowerCase() + p.slice(1);
                el.style[prefix + p] = style;   
            }else{
                el.style[prefix + p] = style;   
            }

        });
    }
    function posOnScreen(el){
        return el.getBoundingClientRect();
    }

    /*
        iterate over the store,
        get each element and apply the right rotation angles.
        Invert the view angle if set.
    */
    function followElements( e ){
        [].forEach.call( store , function(item, index){
            sPos = posOnScreen( item.element );
            /* if the element is in the viewport */
            if( sPos.top > -sPos.height || sPos.top < document.documentElement.clientHeight + sPos.height){
                invert = item.invert ? -1 : 1;

                xdeg = -90 * invert * ( e.clientX - sPos.left ) / document.documentElement.clientWidth + "deg";
                ydeg = 90 * invert * ( e.clientY - sPos.top ) / document.documentElement.clientHeight + "deg";
                prefixStyle(item.element,"transform","rotateY("+xdeg+") rotateX("+ydeg+")");
            }else{
            }
        });
    }

    /* public methods */
    /*
    add an element to the store.
    usage:
        MouseFollower.add({
            element: document.querySelector(".cube"),
            invert: true
        });
    */
    function add( opt ){
        if( opt && opt.element ){
            store.push( opt );
        }
    }
    //TODO
    function remove(arguments) {
    }
    function stop() {
        store = [];
    }

    return {
        add: add,
        remove: remove,
        stop: stop
    }
})();

項目主頁：http://www.baiduhome.net/lib/view/home/1390182824632