1 년 전 · ca80c0fa46
--- a/day22/html/1.let.html
+++ b/day22/html/1.let.html
@@ -0,0 +1,11 @@
 
				+<!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 src="../js/1.let.js"></script>
			
 
				+</body>
			
 
				+</html>
			
--- a/day22/html/2.变量提示.html
+++ b/day22/html/2.变量提示.html
@@ -0,0 +1,11 @@
 
				+<!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 src="../js/2.变量提升.js"></script>
			
 
				+</body>
			
 
				+</html>
			
--- a/day22/html/3.const.html
+++ b/day22/html/3.const.html
@@ -0,0 +1,11 @@
 
				+<!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 src="../js/3.const.js"></script>
			
 
				+</body>
			
 
				+</html>
			
--- a/day22/js/1.let.js
+++ b/day22/js/1.let.js
@@ -0,0 +1,41 @@
 
				+// var a = 100;
			
 
				+var c='111';
			
 
				+console.log(c,'c');
			
 
				+// 声明变量
			
 
				+/**
			
 
				+ * let 特点
			
 
				+ * 1.let 不可以重复声明
			
 
				+ * 2.let 作用在块级作用域内
			
 
				+ * 3.let 不具有变量提示
			
 
				+ * 4.在临时区域内 不允许重复声明let
			
 
				+ */
			
 
				+let b = 10;
			
 
				+b = '1000';
			
 
				+console.log(b,'b');
			
 
				+
			
 
				+function fn1() {
			
 
				+    var c = 10;
			
 
				+    console.log(c,'函数中')
			
 
				+}
			
 
				+fn1();
			
 
				+let a1 = 10;
			
 
				+let b1 = 20;
			
 
				+a1 = 30;
			
 
				+b1 = 40;
			
 
				+console.log(a1,b1,'打印');
			
 
				+
			
 
				+console.log(c,'c1');
			
 
				+
			
 
				+var a2 = true;
			
 
				+if(a2) {
			
 
				+    let x = 100;
			
 
				+    
			
 
				+    // console.log(x,'打印的1')
			
 
				+}
			
 
				+// let x = 1;
			
 
				+// console.log(x,'打印的x')
			
 
				+
			
 
				+for(var i=0;i<10;i++) {
			
 
				+    console.log(i,'ii')
			
 
				+}
			
 
				+console.log(i,'22')
			
--- a/day22/js/2.变量提升.js
+++ b/day22/js/2.变量提升.js
@@ -0,0 +1,8 @@
 
				+console.log(a,'a');
			
 
				+var a = 10;
			
 
				+console.log(a,'a1');
			
 
				+
			
 
				+// 通过var定义变量 会把当前定义变量的作用域提到最上面 但是不赋值
			
 
				+
			
 
				+// console.log(b,'b')
			
 
				+let b = 111;
			
--- a/day22/js/3.const.js
+++ b/day22/js/3.const.js
@@ -0,0 +1,22 @@
 
				+/**
			
 
				+ * const 特点
			
 
				+ * 1.一般用于声明常量 
			
 
				+ * 2.变量名大写
			
 
				+ * 3.不能重复声明
			
 
				+ * 4.不能重复赋值 不能修改
			
 
				+ * 5.不具备变量提升
			
 
				+ * 6.块级作用域
			
 
				+ */
			
 
				+const PI = 3.14;
			
 
				+console.log(PI,"PI")
			
 
				+// PI = 111;
			
 
				+// console.log(PI,"PI1")
			
 
				+for(let I = 0;I<10;I++) {
			
 
				+    console.log(I,'I')
			
 
				+}
			
 
				+console.log(I,'2')
			
 
				+// var a = true;
			
 
				+// if(a) {
			
 
				+//     const B = 2;
			
 
				+// }
			
 
				+// console.log(B,'B')