fengchuanyu 4 月之前
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a330ee034f
共有 3 個文件被更改,包括 111 次插入0 次删除
  1. 20 0
      6_ES6/4_const.html
  2. 39 0
      6_ES6/5_栈内存&堆内存.html
  3. 52 0
      6_ES6/6_字符串扩展.html

+ 20 - 0
6_ES6/4_const.html

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+<!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>
+        let a = 10;
+        const b = 20;
+        let c = a+b;
+        a = "hello";
+        b = 111;
+        // const 定义的是常量 不能修改
+        console.log(a,c,b);
+        
+    </script>
+</body>
+</html>

+ 39 - 0
6_ES6/5_栈内存&堆内存.html

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+<!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>
+        // let a = 10;
+        // let b = a;
+        // a = 20;
+        // console.log(b);
+
+        // let arr = [1,2,3];
+        // let arr2 = arr;
+        // arr[1] = "a";
+        // console.log(arr2);
+
+        // let obj = {
+        //     name: "张三",
+        //     age: 18
+        // }
+        // let obj2 = obj;
+        // obj.name = "李四";
+        // console.log(obj2);
+
+        let arr = [1,2,3,4,5,['a','b','c']];
+        let arr2 = [];
+        for(let i=0;i<arr.length;i++){
+            arr2.push(arr[i]);
+        }
+        arr[0] = 100;
+        arr[5][0] = "x";
+        console.log(arr2,arr);
+
+    </script>
+</body>
+</html>

+ 52 - 0
6_ES6/6_字符串扩展.html

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+<!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>
+    <div id="box">
+        <!-- <h1 id="test-h1">hello</h1> -->
+    </div>
+    <script>
+        // var str = "hello";
+        // var oBox = document.getElementById('box');
+        // // var oH1 = "<h1 id='test-h1'>"+str+"</h1>";
+        // // 模版字符串
+        // let oH1 = `<h1 id="test-h1">${str}</h1>`;
+
+        // oBox.innerHTML = oH1;
+        
+        // var str = "hello";
+        // console.log(str.includes("o"));
+        // console.log(str.indexOf("x"));
+        // 判断当前字符串是否以某个字符串开头
+        // console.log(str.startsWith("he"));
+        // 判断当前字符串是否以某个字符串结尾
+        // console.log(str.endsWith("lo"));
+        // 重复字符串
+        // console.log(str.repeat(3));
+        // padStart 从头部开始填充 第一个参数使当前字符串变成多长第二个参数是填充的字符串
+        // console.log(str.padStart(10,"ab"));
+        // padEnd 从尾部开始填充
+        // console.log(str.padEnd(10,"ab"));
+        
+        // var str = "   hello    ";
+        // console.log(str);
+        // trim 去除字符串两端的空格
+        // console.log(str.trim());
+        // trimStart 去除字符串前端的空格
+        // console.log(str.trimStart());
+        // trimEnd 去除字符串后端空格
+        // console.log(str.trimEnd());
+        
+        // var str = "hello";
+        // console.log(str.charAt(0));
+        // console.log(str.at(0));
+        
+        
+        
+    </script>
+</body>
+</html>