Array.prototype.fst = function(fn){
var fn = fn || function(a, b){ return a > b;};
for(var i=0; i<this.length; i++){
for(var j=i; j<this.length; j++){
if(fn(this[i], this[j]) > 0){
var t = this[i];
this[i] = this[j];
this[j] = t;
}
}
}
return this;
};