学步园

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 ;