1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
  6.     <title>Document</title>
  7. </head>
  8. <body>
  9.     <script>
  10.         var zhou = {
  11.             "name":"zhou",
  12.             "sex":"男",
  13.             "age":18
  14.         }
  15.         var obj={
  16.             name:"zhang",
  17.             sex:"女"
  18.         }
  19.         console.log(zhou.name)
  20.         zhou.skill="javascript"
  21.         console.log(zhou)
  22.     </script>
  23. </body>
  24. </html>

1.JSON-Array

数组-对象的混合

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 数组-对象的混合
        var students = [{name:"叶",age:18},{name:"蒋",age:17}]
        var hots = [{img:"xxx",name:"xxx",playcount:12}]
    </script>
</body>
</html>

2.function

封装一段特定功能的代码块

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        go();
        // function封装一段特定功能的代码块
        function go(){
            console.log("hello world");
        }
        // go();
    </script>
</body>
</html>

3.函数的参数

x,就是函数的参数
函数的参数是局部变量

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // x,就是函数的参数  
        // 函数的参数是局部变量
        function show(x){

            console.log(x)
        }
        console.log(x);
        show(3);
    </script>
</body>
</html>

4.全局变量和局部变量

在函数里面使用var定义的变量(包含函数的参数)—局部变量
函数的参数是局部变量
函数外面声明的变量—全局变量

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 在函数里面使用var定义的变量(包含函数的参数)--局部变量
        // 函数的参数是局部变量
        // 函数外面声明的变量--全局变量
        var a = 10;
        function show(){
            console.log(a);
            var b = 20;
            console.log(b);
        }
        show();
        console.log(b);
    </script>
</body>
</html>

5.for循环

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        var arr = ["html", "css", "javascript", "vue"];

        for (var i = 0; i < arr.length; i++) {
            console.log(arr[i])
        }

    </script>
</body>

</html>

6.review

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var obj= {
            name:"zhou",
            age:18
        }
        console.log(obj.name)
        console.log(obj["name"])
    </script>
</body>
</html>

7.!

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var a = 190;
        console.log(!a);
    </script>
</body>
</html>