arr[i]
    indexOf —查询数组某个值的下标
    slice(starIndex,endIndex)不包含endIndex
    slice(startIndex) 截取从startIndex开始到后面所有的值

    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 arr = [1,2,3,4]
    11.         // arr[i]
    12.         // indexOf --查询数组某个值的下标
    13.         // slice(starIndex,endIndex)不包含endIndex
    14.         // slice(startIndex)  截取从startIndex开始到后面所有的值
    15.         console.log(arr.indexOf(4));
    16.         console.log(arr.slice(1,3));
    17.         console.log(arr.slice(1));
    18.     </script>
    19. </body>
    20. </html>

    1.PNG