var timer;

$(function(){

//捲軸滾動觸發

$(window).scroll(function(){

clearInterval(timer);

var topScroll=getScroll();

var topDiv="100px";

var top=topScroll+parseInt(topDiv);

timer=setInterval(function(){

//動畫移動

$(".test").animate({"top":top},500);

},500)

})

})

function getScroll(){

var bodyTop = 0;

if (typeof window.pageYOffset != "undefined") {

bodyTop = window.pageYOffset;

} else if (typeof document.compatMode != "undefined" && document.compatMode != "BackCompat") {

bodyTop = document.documentElement.scrollTop;

}

else if (typeof document.body != "undefined") {

bodyTop = document.body.scrollTop;

}

return bodyTop

}