12:12

原因在於scroll時動畫不斷重新play，在progress加上.pause()即可解決：
$(window).on("scroll", function(){
var top = $(window).scrollTop();
var percentofprogress=(top+$(window).height())/($(document).height()-$(window).height());
//console.log(top);
//console.log(top/($doc.height()-$win.height()));
tl.progress(percentofprogress).pause();
} )

筆記一下( 5月lovelybox html )
var add = document.getElementById("big1");
var image = new Image();
image.onload=function(){
add.appendChild(image);
$(add).animate({opacity:0.5},0).animate({opacity:1},250);
}
var imgurlary = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t"];
function dfun() {
for(var i = 0;i < 20;i++) {
(function(i) {
$("#small" + String(i + 1)).mouseover(function() {
image.src="stylesheets/images/products_"+imgurlary[i]+".png";
}).mouseout(function(){add.removeChild(image)})
}
)(i)
}
}
dfun();