If your hair is brown, purple probably isn't going to show up very well. It's best to bleach your hair before dying it an unnatural color. Like I told you before, the box says 30-40 minutes, but the most I'd leave it on for is an hour. And that's at your own judgment, too.
But China's population statistics can be particularly misleading. Virtually overnight, Chongqing has become the largest city not only in China, but in the world, Time Magazine proclaimed in 2005. But it wasn't true-Chongqing is not the largest city in the world, or even in China.
Shanghai is the largest city in Asia and the world, with over 20 million residents. It's located in China. The largest metropolitan area (city and suburbs) is Tokyo, the capital of Japan, with around 35 million inhabitants. China plans to build a mega city though, with over 100 million people in though.