JavaScript function to get the position coordinates for a DOM element.

/**
 * Gets the position coordinates for an element.
 *
 * @example
 *   var coordiantes = getElementPosition( document.getElementById('el') );
 *   >>> Object { x: 0, y: 0, width: 1350, height: 45 }
 *
 * @param {DOM.Element} element The DOM Element.
 * @return {Object} An object containing the position coordinates for the passed
 *     DOM Element. Example: Object { x: 0, y: 0, width: 1350, height: 45 }.
 */
function getElementPosition(element) {
    var result = {};
    result.x = 0;
    result.y = 0;
    result.width = 0;
    result.height = 0;

    if (element.offsetParent) {
        result.x = element.offsetLeft;
        result.y = element.offsetTop;

        var parent = element.offsetParent;
        while (parent) {
            result.x += parent.offsetLeft;
            result.y += parent.offsetTop;
            var parentTagName = parent.tagName.toLowerCase();
            if (parentTagName != "table" &&
                parentTagName != "body" &&
                parentTagName != "html" &&
                parentTagName != "div" &&
                parent.clientTop &&
                parent.clientLeft) {
                result.x += parent.clientLeft;
                result.y += parent.clientTop;
            }
            parent = parent.offsetParent;
        }
    } else if (element.left && element.top) {
        result.x = element.left;
        result.y = element.top;
    } else {
        if (element.x) {
            result.x = element.x;
        }
        if (element.y) {
            result.y = element.y;
        }
    }

    if (element.offsetWidth && element.offsetHeight) {
        result.width = element.offsetWidth;
        result.height = element.offsetHeight;
    } else if (element.style && element.style.pixelWidth && element.style.pixelHeight) {
        result.width = element.style.pixelWidth;
        result.height = element.style.pixelHeight;
    }

    return result;
}