数组去重

Array.prototype.unique = Array.prototype.unique || function (){
var arr = [];
for (var i = 0,len = this.length; i < len; i++){
if(arr.indexOf(this[i]) == -1){
arr.push(this[i]);
}
}
return arr;
};

1     Array.prototype.unique = Array.prototype.unique || function (){
var arr = [this[0]];
for(var i = 1,len = this.length; i < len; i++){
if(this.indexOf(this[i]) == i){
arr.push(this[i]);
}
}
return arr;
};

console.log([1,2,3,5,2,3].unique());  //[1,2,3,5]

1   Array.prototype.unique = Array.prototype.unique || function (){
var n = {},
arr = [];
for(var i = 0,len = this.length; i < len; i++){
if(!n[this[i]]){
n[this[i]] = true;
arr.push(this[i]);
}
}
return arr;
};

console.log([1,2,3,5,2,3].unique()); //[1,2,3,5]