Js获取元素在页面里的坐标位置和宽高

//获取元素在页面里的位置和宽高
function getPosition(obj) {
    var top = 0,
        left = 0,
        width = obj.offsetWidth,
        height = obj.offsetHeight;

    while(obj.offsetParent){
        top += obj.offsetTop;
        left += obj.offsetLeft;
        obj = obj.offsetParent;
    }

    return {"top":top,"left":left,"width":width,"height":height};
}