function scroll() {

    //ie9+ 标准浏览器

    if (window.pageYOffset != null) {

      return {

        left: window.pageXOffset,

        top: window.pageYOffset

      }

    }

    //声明DTD的

    else if (document.compatMode === "CSS1Compat") {

      return {

        left: document.documentElement.scrollLeft,

        top: document.documentElement.scrollTop

      }

    }

    //未声明DTD

    return {

      left: document.body.scrollLeft,

      top: document.body.scrollTop

    }

  }