Countdown using JavaScript

It's a clock countdown demo using JavaScript.

html

The concise html contains a div named container. And the input area is the place where we can set up the input text area which will be added with JavaScript. The time is for showing the countdown time section.

css

When hovering the input text box, the background color will turn blue. And all content keep in the middle of the site.

js1

js2

The thought of the countdown clock:
when the window onload, the text box and star-button should be created,meanwhile the attributes set one by one.Then insert all we created into the inputArea div in the html.
When click the start button, we can triger an event named startCountdown.
Getting the value of input and translating to the time to seconds.
Launching the function tick every second.
Taking the calculation to get minutes and seconds and display in the time section.
When the remaining time goes to zero, we should reset the time section to original 00:00.