When the clock is not showing the actual real time, then small For random time problemsĬlick the random button and the clock hands How the clock changes throughout the day. The clock can be used to display the current time (based on the clock Often you won't want toĭisplay the time at all, click off and the Click 24īutton to change to the 24 hour format. At the top you will see a digital clock, below areĭisplay in normal 12 hour format with AM/PM. Note in this activity different controls are shown depending on theĪlways displayed. The clocked can be altered to change colors and its overall styling. The third mode uses the clock as a way to help understand fractions. The second mode uses the the clock hands as a way of learning angles.
Adjustable dclock timer how to#
The first demonstrates how to tell the time using an analogue clock. The clock for learning time has movable hands. This.minutes = Math.Interactive Clock with analog and digital display Introduction Var diffInSeconds = Math.floor((new Date() - this.startedTime) / 1000) Since setInterval is not reliable in inactive windows/tabs we are using date diff. And you'd probably want to add some kind of get/set function if you wanted to get the count or change the repeat value. Comes in handy.Įdit: Note, this doesn't do any input checking (like if delay and repeat are the correct type.
Self-corrects the setTimeout, can run it X number of times (-1 for infinite), can start running instantaneously, and has a counter if you ever need to see how many times the func() has been run. * Self-adjusting interval to account for drifting I've wrapped it up into a constructor function so we can do 'objecty' things with it. I'ma just build on Bergi's answer (specifically the second part) a little bit because I really liked the way it was done, but I want the option to stop the timer once it starts (like clearInterval() almost). SetTimeout(step, Math.max(0, interval - dt)) // take into account drift possibly special handling to avoid futile "catch up" run Var dt = Date.now() - expected // the drift (positive for overshooting) Here the exact delay for each of the repeated timeouts is adapted to the actually elapsed time, compared to the expected intervals: var interval = 1000 // ms Those are known as self-adjusting timers. This requires a bit more advanced strategy (and code), though it pays out well (and registers less timeouts). However, sometimes you really need a steady interval executing your callbacks without drifting.
Adjustable dclock timer update#
So it would be advisable to update more often, like about every 100ms, to avoid such jumps. When the interval lags a bit and executes your callback after 990, 1993, 2996, 3999, 5002 milliseconds, you will see the second count 0, 1, 2, 3, 5 (!). Now, that has the problem of possibly jumping values. alternatively just show wall clock time: Output(Math.floor(delta / 1000)) // in seconds Var delta = Date.now() - start // milliseconds elapsed since start Then base your logic on the current time value, instead of counting how often your callback has been executed.įor a simple timer or clock, keep track of the time difference explicitly: var start = Date.now() Use the Date object instead to get the (millisecond-)accurate, current time. They are allowed to lag arbitrarily, and they do not keep a constant pace but tend to drift (as you have observed). They cannot be trusted, there are no accuracy guarantees for them. Because you are using setTimeout() or setInterval().
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