From my comment: I would use setTimeout [docs] and always call it when the previous response was received. This way you avoid possible congestion or function stacking or whatever you want to call it, in case a request/response takes longer than your interval. So something like this: function refresh() { // make Ajax call here, … Read more
The reason setInterval is bad is because it will try to execute the code every X MS regardless of what’s going on in the thread. So if you have: setInterval( complexFunction, 1 ); // complexFunction takes >1 MS to complete …you may end up with setInterval trying to re-execute several times before even its own … Read more
I don’t think setInterval is inherently going to cause you significant performance problems. I suspect the reputation may come from an earlier era, when CPUs were less powerful. There are ways that you can improve the performance, however, and it’s probably wise to do them: Pass a function to setInterval, rather than a string. Have … Read more
Browser set a minimal value for the interval. Usualy 10ms, but it can depend on the browser. This means repeat this as fast as I’m possibly allowed. The W3C spec say 4ms : http://www.whatwg.org/specs/web-apps/current-work/multipage/timers.html#timers This is correct but probably reveal a design error. EDIT: By the way, it is bad practice to pass a string … Read more
var list = [1, 2, 3, 4, 5]; for (var i = 0, len = list.length; i < len; i += 1) { (function(i) { setInterval(function() { list[i] += 10; console.log(i + “=>” + list[i] + “\n”); }, 5000) })(i); } Here is the working code: var list = [1, 2, 3, 4, 5]; for … Read more
You have to store the timer id of the interval when you start it, you will use this value later to stop it, using the clearInterval function: $(function () { var timerId = 0; $(‘textarea’).focus(function () { timerId = setInterval(function () { // interval function body }, 1000); }); $(‘textarea’).blur(function () { clearInterval(timerId); }); });
Returns a value which can be used to cancel the timer. So, it would seem unlikely that they return the same value (unless they are reusing values and one of the timers has already been cancelled) Mozilla states it’s DOM level 0, but not part of the specification. (look at the bottom of the page) … Read more
If by “restart”, you mean to start a new 4 second interval at this moment, then you must stop and restart the timer. function myFn() {console.log(‘idle’);} var myTimer = setInterval(myFn, 4000); // Then, later at some future time, // to restart a new 4 second interval starting at this exact moment in time clearInterval(myTimer); myTimer … Read more
I think I may have figured out a solution. I figured, if you can measure it you can compensate for it, right? http://jsfiddle.net/zryNf/9/ var start; var nextAt; var f = function() { if (!start) { start = new Date().getTime(); nextAt = start; } nextAt += 1000; var drift = (new Date().getTime() – start) % 1000; … Read more
You can create a setTimeout loop using recursion: function timeout() { setTimeout(function () { // Do Something Here // Then recall the parent function to // create a recursive loop. timeout(); }, 1000); } The problem with setInterval() and setTimeout() is that there is no guarantee your code will run in the specified time. By … Read more