JS-获取元素的左上右下距离

    <script type="text/javascript">
    function getElementLeft(element){
        var actualLeft = element.offsetLeft;
        var current = element.offsetParent;
        while (current !== null){
            actualLeft += current.offsetLeft;
            current = current.offsetParent;
        }
        return actualLeft;
    }
    function getElementTop(element){
        var actualTop = element.offsetTop;
        var current = element.offsetParent;
        while (current !== null){
            actualTop += current. offsetTop;
            current = current.offsetParent;
        }
        return actualTop;
    }
    function getBoundingClientRect(element){
        var scrollTop = document.documentElement.scrollTop;
        var scrollLeft = document.documentElement.scrollLeft;
        if (element.getBoundingClientRect){
            if (typeof arguments.callee.offset != "number"){
                var temp = document.createElement("div");
                temp.style.cssText = "position:absolute;left:0;top:0;";
                document.body.appendChild(temp);
                arguments.callee.offset = -temp.getBoundingClientRect().top - scrollTop;
                document.body.removeChild(temp);
                temp = null;
            }
            var rect = element.getBoundingClientRect();
            var offset = arguments.callee.offset;
            return {
                left: rect.left + offset,
                right: rect.right + offset,
                top: rect.top + offset,
                bottom: rect.bottom + offset
            };
        } else {
            var actualLeft = getElementLeft(element);
            var actualTop = getElementTop(element);
           return {
                left: actualLeft - scrollLeft,
                right: actualLeft + element.offsetWidth - scrollLeft,
                top: actualTop - scrollTop,
                bottom: actualTop + element.offsetHeight - scrollTop
            }
        }
    }
    function getDimensions(){
        var rect = getBoundingClientRect(document.getElementById("myDiv"));
        alert("left: " + rect.left + "\nright: " + rect.right  + "\ntop: " + rect.top + "\nbottom: " + rect.bottom);
    }
    </script>