<!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;
??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>
2017-02-17
setTimeout("startCount()",1000);在startCount()這個函數里被調用，屬于遞歸調用，會反復被執行。