示例7：value > min(min默认为0)
| 进度：<meter value="0.5"></meter> |
示例8：value < high
| 进度：<meter value="0.5" high="0.8"></meter> |
示例9：value = high
| 进度：<meter value="0.8" high="0.8"></meter> |
示例10：value > high
| 进度：<meter value="0.9" high="0.8"></meter> |
示例11：value < low
| 进度：<meter value="0.1" low="0.25"></meter> |
示例12：value = low
| 进度：<meter value="0.25" low="0.25"></meter> |
