lovecoding
/
VIP22


			
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							<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    var a = 123;//数字 Number
    console.log(a)

    var b = '小明xxxx123!@#$%%';// 字符串 String   里面可以写任意内容
    console.log(b)

    var c = true;//布尔值  Boolean  只有两个值  一个是true  一个是false
    console.log(c)

    var d = '123'
    console.log(d)

    var e;//undefined   能找到变量名称  但是没有值
    console.log(e)

    //typeof 是检测一个变量的数据类型
    console.log(typeof a)//number 
    console.log(typeof b)//string
    console.log(typeof c)//boolean
    console.log(typeof e)//undefined


    a = 'hahaha';
    console.log(a)
  </script>
</body>
</html>