Array.prototype.combinate = function( iItems, aIn ) {
    if (!aIn) {
        var aIn = new Array();
        this.combinate.aResult = new Array();
    }
    
    for(var i = 0; i < this.length; i++) {
        var a = aIn.concat(this[i]);
        var aRest = this.concat(); // Concat with nothing to create copy
        aRest.splice(0, i + 1);
        
        if(iItems && iItems - 1 <= aRest.length) {
            aRest.combinate(iItems - 1, a);
            if(iItems == 1) this.combinate.aResult.push(a);
        }
    }
    
    return this.combinate.aResult;
}