為什么sum能無限循環加
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
var num=0;
function numCount(){
?document.getElementById('txt').value=num;
?num=num+1;
?setInterval("numCount()",1000);
?}
</script>
</head>
<body>
<form>
<input type="text" id="txt" />
<input type="button" value="Start" onClick="numCount()" />
</form>
</body>
</html>
2018-05-07
因為函數numCount()調用了自己