Usable Code

Alright, This is the main code of the Clock API that you can copy.

First, to use the days, You need this array:

const days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"];

And if you've got that array, this is the Get Day code:

const todayIndex = new Date().getDay(); // Gets today's day from 0-6
      const currentDayName = days[(todayIndex + 6) % 7]; // Shifts the days from 0-6 to 1-7 to match our
// array, and links the array so we get the day.

Let's move on to the Get Time Code (Accurate Version)

setInterval(() => {
        const now = new Date();
        const hour = now.getHours();
}, 1000);

Use:

         now.toLocaleTimeString();

In your code to get the time in 00:00:00 format, such as:

 document.getElementById("showtime").innerText = "The Time is " + now.toLocaleTimeString();

Tip: Put this inside the setInterval 👆

And the const hour can be used like this example:

        if (hour >= 12) {
   document.getElementById("TimeText").innerText = "It's after 12 O' clock!";
}

Here is how to get the date:

const today = new Date();
      const date = today.toLocaleDateString();

And finally, Here is how to get the timezone:

const timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;