var arr = [11,22,334,44,55,66];

var store = [];

​

var result = arr.slice(0).every(function(item, index, array){

  if(store.indexOf(item) > -1){

    array.length=0;

    return false;

  }else{

    store.push(item);

    return true;

  }

});

​

console.log(result);

​

Array.prototype.isUnique = function() {

    var uniq = [];

    var result = this.slice(0).every(function(item, index, arr) {

        if (uniq.indexOf(item) > -1) {

            arr.length = 0;

            return false;

        } else {

            uniq.push(item);

            return true;

        }

    });

    return result;

};

​

console.log(arr.isUnique());

​