<script?type="text/javascript">
???function?clock(){
??????var?time=new?Date();???????????????	??
??????document.getElementById("clock").value?=?time;
???}
????var?idOfSetInterval;
????
????function?startClock(){
????????alert("?你好");
????????idOfSetInterval?=?setInterval(clock,1000);
????}
????function?endClock(){
????????alert("結(jié)束")
????????clearInterval(idOfSetInterval);
????}
</script>

我發(fā)現(xiàn)沒有調(diào)用startClock()時setInterval()已經(jīng)執(zhí)行了，這是為什么呢？并且通過函數(shù)調(diào)用clearInterval()也沒有產(chǎn)生預(yù)期的效果。