請問為什么這個會循環，難道setTime()有循環功能
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
var num=0;
function numCount(){
document.getElementById('txt').value=num;
num=num+1;
setTimeout("numCount()",1000);
}
</script>
</head>
<body>
<form>
<input type="text" id="txt" />
<input type="button" value="Start" onClick="numCount()" />
</form>
</body>
</html>
2017-05-13
這個函數在自己的函數體中調用了自己，所以每過一秒都能執行一遍這個函數
2017-05-31
這叫遞歸
2017-05-22
//這個就不會
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>計時器</title>
<script type="text/javascript">
? var num=0;
? function startCount() {
? ? document.getElementById('count').value=num;
? ? num=num+1;
? ??
? }
? setTimeout("startCount()",1000);
</script>
</head>
<body>
<form>
<input type="text" id="count" />
<input type="button" value="click it" onclick="startCount()">
</form>
</body>
</html>