How to limit the number of iterations done by setInterval

Question

I display video ads to my users. I don\'t host these ads by the way; I get them from another company.

When ever an ad is clicked it leaves a cookie in the user\'s b

Answer 1

Passing a Callback to the Interval Function, which in turn updates a counter in the global scope:

var countIntervals = 0,
    intervalFunc = function(_callback){

        console.log(countIntervals);

        if(countIntervals > 5) {            
            clearInterval(setIntervalVar);
        } else {
            // do stuff
            _callback();
        }
    };

setIntervalVar = setInterval(intervalFunc.bind(null, function(){
    countIntervals++;
}), 500);

Answer 2

WindowTimers.setInterval(func, delay[, param1, param2, ...])

The 3^rd parameter and onward in setInterval are optional parameters to pass to the interval function. Note, these optional arguments are not supported in IE9 and earlier.

We can use this to our advantage by avoiding the use of global or outside-scope. as seen below. The interval function keeps track of the limit and the current increment of the counter through the opts parameter.

The runTask function takes a mandatory fn argument which returns a boolean value to determine if the timer's task has been completed. There are two taks that are run in the example below, with each varying in the rate at which each is run and the condition to be met.

The first two tasks finish, but the last one runs out of attempts before the condition is met.

function writeLine(el, text) {
  el.innerHTML += [].slice.call(arguments, 1).join(' ') + '\n';
}

function runTask(options, interval, limit) {
  var interval = setInterval(function(opts) {
    opts.incr = (opts.incr || 0) + 1;    
    if (opts.fn(opts)) {
      clearInterval(interval);
      writeLine(opts.el, '>> Task finished...');
    } else if (opts.incr > limit) {
      clearInterval(interval);
      writeLine(opts.el, '>> Exceeded limit of ' + limit);
    } else {
      writeLine(opts.el, '>> Attempt: ' + opts.incr + '/' + limit);
    }
  }, interval, options);
}

// 5 atttempts to reach 4 in 250ms.
runTask({
  fn : function(opts) { return opts.incr === 4; },
  el : document.querySelectorAll('div.col')[0]
}, 250, 5);

// 10 atttempts to reach 7 in 100ms.
runTask({
  fn : function(opts) { return opts.incr === 7; },
  el : document.querySelectorAll('div.col')[1]
}, 100, 10);

// 10 atttempts to reach 15 in 50ms.
runTask({
  fn : function(opts) { return opts.incr === 15; },
  el : document.querySelectorAll('div.col')[2]
}, 50, 10);

.col {
  display: inline-block;
  width: 175px;
  font-family: monospace;
  white-space: pre;
  border: thin solid black;
  vertical-align: top;
  padding: 4px;
}

<div class="col"></div>
<div class="col"></div>
<div class="col"></div>

Answer 3

This should do it:

function checkCookie() {
    var cookie = getCookie("PBCBD2A0PBP3D31B");
    if (cookie != null && cookie != "") {
        alert("You clicked on an ad");
    }
    if (counter > 10) clearInterval(clr);
    counter++;
    clr = setInterval(function(){checkCookie()}, 10000);​
}
var counter = 0;
checkCookie();

Answer 4

When you call setInterval, it returns you an interval ID that you can then use to stop it by calling clearInterval. As such, you'll want to count the iterations in a variable, and once they've reached a certain count, use clearInterval with the ID provided by setInterval.

var iterations = 0;
var interval = setInterval(foo, 10000);
function foo() {
    iterations++;
    if (iterations >= 5)
        clearInterval(interval);
}

Live example

Answer 5

You just need some sort of global counter variable to keep track. For instance, the follow code would only run the cookie check a maximum of 20 times per page load.

var numChecks = 0;

function checkCookie()
{
    ...

    numChecks++;
    if (numChecks < 20) setTimeout("checkCookie()", 10000);
}

setTimeout("checkCookie()", 10000);