javascript 随机生产小数

	function random(maxNum, minNum, decimalNum) {
			var max = 0, min = 0;
			minNum <= maxNum ? (min = minNum, max = maxNum) : (min = maxNum, max = minNum);
			switch (arguments.length) {
				case 1:
					return Math.floor(Math.random() * (max + 1));
					break;
				case 2:
					return Math.floor(Math.random() * (max - min + 1) + min);
					break;
				case 3:
					return (Math.random() * (max - min) + min).toFixed(decimalNum);
					break;
				default:
					return Math.random();
					break;
			}
		}