Code:
window.onscroll = function (e) {
var basediv = document.getElementById('basediv').offsetTop;
var setdiv = document.getElementById('setdiv');
var top=getScroll()[1];
if (top < basediv) {
setdiv.style.top = "0px";
}
else {
setdiv.style.top = top - basediv + "px");
}
}
function getScroll(){
if (window.innerHeight){
return [window.pageXOffset,window.pageYOffset];
}
else if (document.documentElement.clientHeight){
return [document.documentElement.scrollLeft,document.documentElement.scrollTop];
}
return [document.body.scrollLeft,document.body.scrollTop];
}