papadavis47 / js-clock-intervals

JavaScript Clock Intervals

Create a webpage that displays a clock where the second, minute, and hour hands tick.

Write CSS to have the clock face, second, minute, hour hands all display correctly on top of each other. Make sure the red second hand displays on top of the minute and hour hand. (Try changing the order the div elements are written in the HTML)

Create intervals in the JavaScript file to make the clocks tick.

Use CSS transform rotation to rotate the hands of the clock.

#myElement {
  transform: rotate(45deg);
}

Change CSS values in JavaScript by getting reference to them through the DOM and setting a new value to their CSS properties:

var degrees = 45;

var el = document.getElementById("myElement");
el.style.transform = "rotate(" + degrees + "deg)";

It would be useful to define functions that convert seconds, minutes and hours to how many degrees the hand should be rotated around the clock!

secondRotation(0); // returns 0
secondRotation(59); // returns (59 / 60) * 360

hourRotation(12); // returns 0
hourRotation(5); // returns (5 / 12) * 360

HINT!

Make sure to use the setInterval function to make a ticking function!

setInterval(function(){
    console.log("TICK!");
 }, 1000);

The first argument is a callback function - it gets triggered every 1000 milliseconds (1 second), which is the second argument.

setInterval(functionYouWantToRun, millisecondsDelay);

Bonus: Show Actual Time

Use JavaScripts Date objects to display the actual time.

var now = new Date();

Get now by declaring a new Date object. You can google for "MDN date methods" to see what helpful methods are attached to Date objects. There's helpful things like .getMonth(), .getSeconds() and who knows what else!

See the full list of methods in the left sidebar on this site: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date

Licensing

All content is licensed under a CC­BY­NC­SA 4.0 license. All software code is licensed under GNU GPLv3. For commercial use or alternative licensing, please contact [email protected].