From fe023eab3b93d5574a20d83d9241e25a763d6c75 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=98my76572?= <my76572@163.com>
Date: Thu, 26 Nov 2020 00:56:03 +0800
Subject: [PATCH] css

---
 JavaScript/BOM.md                             |  4 ++
 JavaScript/javascript.md                      |  1 +
 .../\344\275\234\347\224\250\345\237\237.md"  | 65 +++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 "JavaScript/\344\275\234\347\224\250\345\237\237.md"

diff --git a/JavaScript/BOM.md b/JavaScript/BOM.md
index e69de29..7fb3e47 100644
--- a/JavaScript/BOM.md
+++ b/JavaScript/BOM.md
@@ -0,0 +1,4 @@
+1. windows
+2. onload
+3. 控制窗口大小
+4. 定时器
\ No newline at end of file
diff --git a/JavaScript/javascript.md b/JavaScript/javascript.md
index 98c6276..da64d72 100644
--- a/JavaScript/javascript.md
+++ b/JavaScript/javascript.md
@@ -9,3 +9,4 @@
 ## [DOM](./DOM.md)
 ## BOM
 ## 事件
+## 作用域
\ No newline at end of file
diff --git "a/JavaScript/\344\275\234\347\224\250\345\237\237.md" "b/JavaScript/\344\275\234\347\224\250\345\237\237.md"
new file mode 100644
index 0000000..6cc1cf1
--- /dev/null
+++ "b/JavaScript/\344\275\234\347\224\250\345\237\237.md"
@@ -0,0 +1,65 @@
+全局作用域： 全局变量：全局作用域的变量  不用var声明的变量
+局部作用域： 局部变量：局部作用域的变量  形参
+````js
+fn();
+console.log(a);
+console.log(b);
+console.log(c);
+function fn(){
+    var a = b = c = 9; // => var a = 9; b = 9; c = 9;
+    //var a = 9,b = 9, c = 9; // => var a = 9,var b = 9, var c = 9;
+    console.log(a);
+    console.log(b);
+    console.log(c);
+}
+
+````
+块级作用域： {}
+
+作用域链：函数内部访问函数外部的变量，通过链式查找函数外部的变量。
+
+预解析：提升变量声明， 提升函数(局部作用域的变量声明也要提升)
+````js
+var num = 10;
+function fn(){
+    console.log(num);  //undefined
+    var num = 20;
+    console.log(num);  //20
+}
+fn();
+
+执行顺序 =>
+var num;
+function fn(){
+    var num;
+    console.log(num);
+    num = 20;
+    console.log(num);
+}
+num = 10;
+fn();
+````
+
+
+js对象
+1. {}  // json 对象
+2. new Object() 
+3. 构造函数  批量生成对象
+````
+function 构造函数(){
+    this.属性;
+    this.方法 = function(){};
+}
+new 构造函数();
+````
+
+new 
+1. 在栈中创造空的对象
+2. 指针指向栈中的对象
+
+遍历：
+for(var key in obj){
+
+}
+
+内置对象
\ No newline at end of file
-- 
Gitee