The keyboard is an external computer device that is easy to break, and it is also an essential computer product. I often use the computer, especially the programmer (yuan) uses it every day; the keyboard is prone to problems. It is very annoying that the words or numbers cannot be typed. Here pcjson.com provides you with an online test tool to test the quality of your keyboard keys. Every time you press a key on the keyboard, the key on the virtual keyboard will be highlighted in color.