.net母板页下获取页面高度(兼容浏览器chrome,IE,firefox)

function getOffSet() {
    if (typeof window.pageYOffset != 'undefined') {
        return window.pageYOffset;//for chrome
    }
    else if (typeof document.compatMode != 'undefined' &&
      document.compatMode != 'BackCompat') {
        return document.documentElement.scrollTop;
    }
    else {
        return document.body.scrollTop;//for IE,firefox
    }
}