function jump(event){
        if(event.keyCode == 38){
            cube.pula();
        }
    }


function walk(){
        if(event.keyCode == 39){
            cube.right();
        }
        if(event.keyCode == 37){
            cube.left();
        }
    }

pula: function(event){
            if(this.jps < 2){
                this.jps++;
                this.v = -this.fp;
            }else if(this.y == 250){
                this.jps = 0;
                this.jps++;
                this.v = -this.fp;
            }
        },

        right: function(){
                if(this.x <= width-64){
                    this.x += this.force;
                }
        },


        left: function(){
            if(this.x >= 15){
                this.x += -this.force;
            }
        },