js 动画效果代码，主要运用setTimeout

function animate(ele,name,from,to,time) {
time = time ||800;
var interval,count,step,now;
interval = 60;
count =Math.round(time/interval);
step = Math.round((to-from)/count);
now = from;
var style = document.getElementById(ele).style;
function go() {
count--;
now = count?now+step:to;
style[name] = now + "px";
if(count) {
setTimeout(go,interval);
}
}

style[name] = from + 'px';
setTimeout(go,interval);
}

<p >
<span id ='s1'>goole!!!!!goole</span>
</p>
<input type="button" value="changeSize" onclick="animate('s1','font-size',9,50,1000)">