JavaScript: How to do something every full hour?

Question

I want to execute some JS code every hour. But I can't use

setInterval("javascript function",60*60*1000);

because I want to do it every full hour, I mean in 1:00, in 2:00, in 3:00 and so on. I am thinking about something like

var d;
while(true) {
  d = new Date();
  if ((d.getMinutes() == '00') && (d.getSeconds() == '00')){
    // my code here
  }  
}

but it's too slow and it doesn't work well.

Thak you for any ideas

Answer 1

I would find out what time it is now, figure out how long it is until the next full hour, then wait that long. So,

function doSomething() {
    var d = new Date(),
        h = new Date(d.getFullYear(), d.getMonth(), d.getDate(), d.getHours() + 1, 0, 0, 0),
        e = h - d;
    if (e > 100) { // some arbitrary time period
        window.setTimeout(doSomething, e);
    }
    // your code
}

The check for e > 100 is just to make sure you don't do setTimeout on something like 5 ms and get in a crazy loop.

Answer 2

What you can do is have an interval run every minute, and check if the time is :00 before running the actual code.

Answer 3

look at this one :

function to_be_executed(){
    ...
    ...
    ...
    makeInterval();
}

function makeInterval(){
    var d = new Date();
    var min = d.getMinutes();
    var sec = d.getSeconds();

    if((min == '00') && (sec == '00'))
        to_be_executed();
    else
        setTimeout(to_be_executed,(60*(60-min)+(60-sec))*1000);
}