Arr删除特定项

 Array.prototype.indexOf = function(val) {            for (var i = 0; i < this.length; i++) {                if (this[i] == val) return i;            }            return -1;        };        Array.prototype.remove = function(val) {            var index = this.indexOf(val);            if (index > -1) {                this.splice(index, 1);            }        };