js 0.0

2021-01-28 09:06:45 +08:00
parent f230cfc37f
commit 5d39890424
18 changed files with 1380 additions and 0 deletions
--- a/js/demo/day3-1.html
+++ b/js/demo/day3-1.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Document</title>
+    <script>
+        var arr=[1,2,3]  //字面量
+        // console.log(arr[1])
+        // for(let i in arr){
+        //     console.log(arr[i])  // i指代的是数组的下标
+        // }
+        arr.push(4)
+        // var q=arr.pop()  //pop 返回的是被删除的那个元素
+        // console.log(arr)
+        // console.log(q)
+        arr.shift()   //删除第一个元素
+        arr.unshift(6)  //往数组首位添加元素
+        console.log(arr)
+
+        var str=arr.join(',')
+        console.log(str)
+
+        console.log(str.split(','))
+
+    //    arr.splice(2,1)
+            arr.splice(2,2,9,0)
+        console.log(arr)
+        // splice()  3  2删除   3修改
+
+    </script>
+</head>
+<body>
+    
+</body>
+</html>