????：<!DOCTYPE html><html><head> <meta charset="utf-8"> <title></title> <!-- <script type="text/javascript"> document.write("Hello Wor
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<!-- <script type="text/javascript">
document.write("Hello World!");
</script> -->
<!-- <script type="text/javascript" src="index.js"></script> -->
</head>
<body>
<script type="text/javascript">
document.write("javascript的變量<br>");
var x=2,y=6;
z=x+y;
document.write(z);
</script>
</body>
</html>
?? ???：西門大官人?? ??：2019-03-03 10:22:34
???? ??：js中的變量分為全局變量和局部變量，你這里定義的是全局變量，最好也定義一下局部變量，并說明一下它們的不同