// JavaScript Document
function getOffset(elem) {
    if (elem.getBoundingClientRect) {
        // "аПб�АаВаИаЛб�Нб�Й" аВаАб�ИаАаНб�
        return getOffsetRect(elem)
    } else {
        // аПб����б�АаБаОб�АаЕб�б�Об��аКаАаК-б�О
        return getOffsetSum(elem)
    }
}

function getOffsetSum(elem) {
    var top=0, left=0
    while(elem) {
        top = top + parseInt(elem.offsetTop)
        left = left + parseInt(elem.offsetLeft)
        elem = elem.offsetParent
    }

    return {top: top, left: left}
}

function getOffsetRect(elem) {
    // (1)
    var box = elem.getBoundingClientRect()

    // (2)
    var body = document.body
    var docElem = document.documentElement

    // (3)
    var scrollTop = window.pageYOffset || docElem.scrollTop || body.scrollTop
    var scrollLeft = window.pageXOffset || docElem.scrollLeft || body.scrollLeft

    // (4)
    var clientTop = docElem.clientTop || body.clientTop || 0
    var clientLeft = docElem.clientLeft || body.clientLeft || 0

    // (5)
    var top  = box.top +  scrollTop - clientTop
    var left = box.left + scrollLeft - clientLeft

    return { top: Math.round(top), left: Math.round(left) }
}