如何取消重復(fù)開啟的計(jì)時(shí)器？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>計(jì)時(shí)器</title>
<script type="text/javascript">
? var num=0;
? var i;
? function startCount(){
? ? document.getElementById('count').value=num;
? ? num=num+1;
? ? i=setTimeout("startCount()",1000);
? }
? function stopCount(){
? ? clearTimeout(i);
? }
</script>
</head>
<body>
? <form>
? ? <input type="text" id="count" />
? ? <input type="button" value="Start" onclick="startCount()" />
? ? <input type="button" value="Stop" onclick="stopCount()" ?/>
? </form>
</body>
</html>
2017-05-31
在函數(shù)??startCount()中插入? clearTimeout(i);
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>計(jì)時(shí)器</title>
<script type="text/javascript">
? var num=0;
? var i;
? function startCount(){
? ??clearTimeout(i);
?document.getElementById('count').value=num;
? ? num=num+1;
? ? i=setTimeout("startCount()",1000);
? }
? function stopCount(){
? ? clearTimeout(i);
? }
</script>
</head>
<body>
? <form>
? ? <input type="text" id="count" />
? ? <input type="button" value="Start" onclick="startCount()" />
? ? <input type="button" value="Stop" onclick="stopCount()" ?/>
? </form>
</body>
</html>