tl;dr: It’s an easy to use web-based timer! Check it out!


It started a little over a year ago, when I learned about the HTML5 Audio API at a local tech event. The presenter went into using the keys of a laptop as a musical keyboard, but my take was to make the tones associated with old-school telephony, the dialtone and DTMF tones, including the A, B, C, and D tones that came with the lineman’s handset.

The next thing that came to mind was the dit dit dit deeeet you’d hear at the end of a timer.

Which made me think about timers.

The way Javascript handles time goes to the millisecond, and is one of the things I really like about the language.

var looper = setInterval( function () {
    if ( condition ) { window.clearInterval(looper) ; }
    }, 1000 ) ;

This will run every second until condition is true. Everything else is a display hack.

Display Hacks Are Tough

Lea Verou gives talks at JS and CSS conferences using only web tools for her presentation software, and man, the things you simply with cascading style sheets is mind-boggling. The amount of CSS I’ve learned after 2001 is dwarfed by the old standbys I learned before, so I look with amazement at the new things, and then promptly forget that was possible, much less how.

One of the things I remembered and used was vw. Even before the rise of Apple’s Retina displays, we weren’t really working at the pixel level, but Retina definitely proved the fiction. What vw gives you is constant size related to window size. If 00:00 fills the width of the screen on your full-screen desktop browser window, it will do so with your phone in landscape mode, your phone on portrait mode, etc.

Requirements and Constraints

I’m an organizer for Purdue Perl Mongers, and we decided that, in order to keep the stress levels down for the December meeeting, we’d go for a Lightning-Talk format which I call Starship Mongers – “Everybody talks. No one quits.” For this, I needed a five-minute timer. I had also been involved in startup-related events where you have five minutes for your pitch. “Tell me when five minutes is up” is a very common thing in my life.

But not everyone need that all the time. I didn’t want to add too much complexity.

(In fact went forward attempting to write Vanilla JS. I use jQuery for most of my work projects, but for this project, I realized that getElementById() was sufficient for my needs, so, as of this writing, it exists in two files. tone.js exists because I have the DTMF code also making sounds, so pulling out the tone generation into a separate class was practical and another good learning experience.)

So the final question was “How do I set the time?” I didn’t want to complicate the high-contrast, high-readability, high-portability interface I had created to make a slow time-setting setup, and sat and wondered for a while.

Then I remembered LifeHacker.

Time was, LifeHacker and other Gizmodo-owned blogs had a clever setup. The URL of the post would be something like Additionally, you scrolled down and another, related post appeared, and the URL became

This uses the fragment part of the URI.


This is normally used with anchor tags. For example, within the page for Tim Berners-Lee in Wikipedia, there appears a tag that says ‘Career’, and following the link takes you directly to when the inventor of the World Wide Web started working.

The good thing with using this, which the DOM refers to as location.hash is that changing it does not require a page reload, which means you can control behavior within your code by hooking a function to window.onhashchange.

The bad thing, of course, is that not every browser supports Javascript, and one of the browsers that doesn’t is the spider that works for Google, so will never show up in the search results. Which is why you don’t see it anymore.

But just because a thing isn’t useful for a blog, that doesn’t mean it isn’t a useful tool, and so I decided that would be how I would set time. #5m0s is my default, but if you bookmark with #25m, you have yourself a Pomodoro timer.

So, please, use my timer. Fork the repo. Make suggestions and improvements. There are animation things I want to do, like not redrawing but still moving forward and beeping and all when the window is not in focus. If you have any questions or comments, I would be glad to hear it. Ask me on Twitter or make an issue on my blog repo.