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NYC · September 21, 2014

Recreating the Union Square Clock with Javascript

On 14th street, just south of Union Square there's a great big digital clock on the side of a building... well, the first time you see it you may not know it's a clock, but it is.

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(Photo by flicker user jStanley)

A photo probably doesn't do it justice, you should probably watch a video to get the full experience.  To the uninitiated, it's unclear what this rapidly-changing series of 15 numbers represents. It's actually 2 clocks, one counting the time that's passed so far today, and one showing how much time is left in the day.

To read it, start at the left: 2 digits for hours, 2 digits for minutes, 2 digits for seconds, 1 digit for 10ths of a second, 1 digit for 100ths of a second.  The right side is in reverse order, counting down: 1 digit for 10ths of second, 2 digits for seconds, 2digits for minutes, 2 digits for hours.

I saw this last night and thought it would be a fun little javascript programming project to replicate this clock on the web... so I did it:

You can link to it on github pages here.  It's responsive, so the numbers should scale for whatever device you load it on.

It's fairly simple, and just uses a lot of javascript's built-in date methods, with a few custom functions to deal with formatting.  An interval runs every 10th of a second and figures out what should be shown.  Check out the code on github.

I can't wait to load it on my phone form Union Square to check my work.

Thanks for reading!

This post was migrated from my old WordPress blog. Embedded maps and links to third-party sites may no longer work.