figure element size using javascript

 //get element size

    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 getViewport() {
        if (document.compatMode == "BackCompat") {
            return {
                width: document.body.clientWidth,
                height: document.body.clientHeight
            };
        } else {
            return {
                width: document.documentElement.clientWidth,
               height:document.documentElement.clientHeight
            };
        }
   }
   
   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
           };
       }
   }