positionElem.js

// Use the test to create a simple element positioning function

function positionElemSimple(elem, x, y){
    elem.style.cssText = "position:absolute;top:" + y + "px;left:" + x + "px;";
    return elem;
}

function positionElem3d(elem, x, y){
    var translate3d = "transform:translate3d(" + x + "px," + y + "px,0);";
    
    // TODO: simplify this
    elem.style.cssText = "position:absolute;" + translate3d + "-webkit-" + translate3d + "-moz-" + translate3d + "-o-" + translate3d + "-ms-" + translate3d + "-khtml-" + translate3d;
    
    return elem;
}

var positionElem = supportsCssTransform3d() ?
    positionElemSimple : positionElem3d;

    
/////

// e.g.
positionElem(myElem, 50, 30);

supportsCssTransform3d.js

/*
    Test browser support for 3D CSS transforms.
    Modified by Premasagar Rose <http://premasagar.com>
    from Modernizr v1.6 <http://modernizr.github.com>
        
*//*global window */

var supportsCssTransform3d = (function(window){
    var document = window.document,
        docElement = document.documentElement,
        docHead = document.head || document.getElementsByTagName('head')[0],
        id = 'modernizr3d',
        m_style = document.createElement(id).style,
        prefixes = ' -webkit- -moz- -o- -ms- -khtml- '.split(' '),   
        undef;

    function testMediaQuery(mq){
        var st = document.createElement('style'),
            div = document.createElement('div'),
            ret;

        st.textContent = mq + '{#' + id + '{height:3px}}';
        docHead.appendChild(st);        
        div.id = id;
        docElement.appendChild(div);
        
        ret = div.offsetHeight === 3;
        docHead.removeChild(st);
        docElement.removeChild(div);
        return ret;
    }

    function test_props(props, callback){
        var i = props.length;
        for (; i; i--){
            if (m_style[ props[i-1] ] !== undef){
                return true;
            }
        }
    }

    return function(){
        var ret = !!test_props(['perspectiveProperty', 'WebkitPerspective', 'MozPerspective', 'OPerspective', 'msPerspective']);
        
        if (ret && docElement.style.webkitPerspective !== undef){
            ret = testMediaQuery('@media ('+prefixes.join('transform-3d),(')+id+')');
        }
        return ret;
    };
}(window));