数组去重

方法一

 var arr=[1,2,3,2,4,4]
 for(var i=0;i<arr.length;i++){
    for(var j=i+1;j<arr.length;j++){
        if(arr[i]==arr[j]){
            arr.splice(j,1);
            j--;
        }
    }
 }

方法二

 function unrepeat(arr) {
        //debugger;
         var newarr = [];
         for (var i = 0; i < arr.length; i++) {
                 if (newarr.indexOf(arr[i]) == -1) {
                         newarr.push(arr[i]);
                 }
         }
         return newarr;
 }
 var num = [3, 5, 8, "3", 1, 6, 5];
 window.onload = function() {
         alert(unrepeat(num));
 }()

方法三:原生js数组去重

function unrepeat(arr) {
        //debugger;
        var newarr = [];
        for (var i = 0; i < arr.length; i++) {
                var isrepeat = false; 
                for (var j = 0; j < newarr.length; j++) {
                        if (arr[i] === newarr[j]) //
                        {
                                isrepeat = true;
                                break;
                        }
                }
                if (!isrepeat) {
                        newarr.push(arr[i]);
                }
        }
        return newarr;
}
var num = [3, 5, 8, "3", 1, 6, 5];
window.onload = function() {
        alert(unrepeat(num));
}();

方法四

 function unrepeat(arr) {
        //debugger;
         var newarr = [];
         for (var i = 0; i < arr.length; i++) {
                 if (newarr.indexOf(arr[i]) == -1) {
                         newarr.push(arr[i]);
                 }
         }
         return newarr;
 }
 var num = [3, 5, 8, "3", 1, 6, 5];
 window.onload = function() {
         alert(unrepeat(num));
 }()

方法五

 Array.prototype.delrepeat = function() {
     var arr = this;
     var _arr = new Array();
     for (var i in arr) {
         if (i == 'delrepeat') continue;
         if (_arr.length == 0) _arr.push(arr[i]);
         for (var j = 0; j < _arr.length; j++) {
             if (arr[i] == _arr[j]) {
                 break;
             }
             if (j > _arr.length - 2) _arr.push(arr[i]);
         }
     }
     return _arr;
 }
 alert([1, 1, 7, ,9,1, 2, 2, 3, 4, 5,9, 5].delrepeat());