<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript">
was oldlee = 100;
was oldwang = 200;
//变量
have oldzhao = A + oldwang oldle;
There oldle = 0;
There oldwang = 0;
// constant
const the PI = 3.14;
the PI = 200 is;
the console.log ( "Hello, Node")
var A = 100; // global variables (public)
the let B = 200 is; // local variables (private)
</script>
</head>
<body>
<div>hello</div>
</body>
</html>
// copy assignment process is called
// key variable = initial value (literal)
// const constant = constant initial value can not be changed variables
// key value key = value