数组中的查重，排序等方法

1. 数组查重：
   利用indexOf（）方法，indexOf 能返回元素在数组中的位置，如果没有返回-1；

        <script>            function fn(arr) {                var result = [];                for (var i = 0; i < arr.length - 1; i++) {                    if (result.indexOf(arr[i])<0) {                        result.push(arr[i]);                    }                }                return result;            }            var arr1=['1','2','3','4','3','1','5'];            console.log(fn(arr1))        </script>        //result=['1','2','3','4'];

1. 数组的排序:
   利用数组中sort（）中的方法

<script>        ar arr1=['1','2','3','4','3','1','5'];        var arr2 = arr1.sort(function(a,b){            return a-b; //1            return b-a; //2        })       console.log(arr2);           </script>    //(7) ["1", "1", "2", "3", "3", "4", "5"]    //(7) ["5", "4", "3", "3", "2", "1", "1"]    ```     3.冒泡排序：    ```    <script>    var arr4=['1','2','3','4','3','1','5','0','45'];       var arr5=[];       for (var i = 0; i <arr4.length; i++) {             var x=Number(arr4[i]);             arr5.push(x);       }       for (var i = 0; i <arr5.length; i++) {         for (var j = 0; j <arr5.length-i; j++) {             if (arr5[j]<arr5[j+1]) {                var empty=arr5[j];                    arr5[j]=arr5[j+1];                    arr5[j+1]=empty;             }         }        }       console.log(arr5);   </script>   //(9) [45, 5, 4, 3, 3, 2, 1, 1, 0]