Javascript Array pushUnique(item)

changePage = function(page){
    window.location.href = '/' + page;
}

Array.prototype.pushUnique = function(item){
    if(this.indexOf(item) === -1) this.push(item);
}

Array.prototype.move = function(oldIndex,newIndex){
 return this.splice(newIndex, 0, this.splice(oldIndex, 1)[0]);
}

Array.prototype.pushUnique = function (item){
    if(this.indexOf(item) === -1) {
        this.push(item);/* w  ww. j  a v a 2 s.co  m*/
        return true;
    }
    return false;
};