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    }  }