自定义随机数

       

               //随机生成一个数 0~20
		function random(range) {
			var max = Math.max(range[0], range[1]);
			var min = Math.min(range[0], range[1]);

			var diff = max - min;// 差值
			var number = Math.ceil(Math.random * diff + min);
                        return number;
		}