只要满足某个条件，返回数组

    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.         // filter   只要满足某个条件，返回数组
    11.         var arr = [1,2,3,4];
    12.         //var res = [];
    13.         //for (var i=0;i<arr.length;i++){
    14.         //    if(arr[i]>2){
    15.         //        res.push(arr[i]);
    16.         //    }
    17.         //}
    18.         //console.log(res)
    19.         var res = arr.filter(item=>item>2);
    20.         console.log(res);
    21.     </script>
    22. </body>
    23. </html>