indexOf arr.indexOf(value) 获取数组的下标

    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=["html","css"]
    11.         // indexOf  arr.indexOf(value) 获取数组的下标
    12.         console.log(arr.indexOf("js"))
    13.     </script>
    14. </body>
    15. </html>

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