Exercise: display clock and stopper

• Create an application that will display the current time on the html page and will constantly update it every second.
• Add a stop and a start button. When 'stop' is clicked time is frozen. When 'start' is clicked display starts to show current time.
• Add a stopper to the page with 3 buttons. Start, Stop, and 'Reset'.
• Add a countdown to the page: An input box wher the user can enter a number. A 'Start' button to start the countdown. Display some message at the end of the countdown.