為什么alert窗口會出現2次？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>alert</title>
? <script type="text/javascript">
? function rec(){
? ? var mychar="I love JavaScript";
alert(mychar);
? }
? </script>
</head>
<body>
? ? <input name="button" type="button" onClick="rec()" value="點擊我，彈出對話框" />
</body>
</html>
2019-05-04
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>alert</title>
? <script type="text/javascript">
? function rec(){
? ? var mychar="I love JavaScript";
alert(mychar);
? }
? </script>
</head>
<body>
? ? <input name="button" type="button" onClick="rec()" value="點擊我，彈出對話框" />
</body>
</html>
2019-04-27
我試了下你的代碼，只彈出了一次alert??！