让一个DIV在页面右边并跟随滚动条移动

function getScroll() {var top, left, width, height;if (document.documentElement && document.documentElement.scrollTop) {top = document.documentElement.scrollTop;left = document.documentElement.scrollLeft;width = document.documentElement.scrollWidth;height = document.documentElement.scrollHeight;}else if (document.body) {top = document.body.scrollTop;left = document.body.scrollLeft;width = document.body.scrollWidth;height = document.body.scrollHeight;}return { top: top, left: left, width: width, height: height };}function scall(){var v = getScroll();//alert(v.top);var e = document.getElementById("float_right");e.style.top = ((v.top) + 50) + "px"; //纵滚动条离顶部距离 }window.onload = scall ;window.onscroll = scall ;