<!-- 優化前 -->
<script type="text/javascript">
function initUI () {
var bd = document.body,
links = document.getElementByTagName("a"),
i=0,
len=links.length;
while(i < len){
update(links[i++]);
}

document.getElementById("go-btn").onclick = function(){
start();
}

bd.className = "active";
}
</script>

<!-- 優化后 -->
<script type="text/javascript">
function initUI () {
var doc=document,
bd = doc.body,
links = doc.getElementByTagName("a"),
i=0,
len=links.length;
while(i < len){
update(links[i++]);
}

doc.getElementById("go-btn").onclick = function(){
start();
}

bd.className = "active";
}
</script>