setinterval | 易学教程

Why does the setInterval callback execute only once?

阅读更多关于 Why does the setInterval callback execute only once?

问题 I have this counter I made but I want it to run forever, it\'s really simple, what am I doing wrong here? function timer() { console.log(\"timer!\") } window.setInterval(timer(), 1000) 回答1: You used a function call instead of a function reference as the first parameter of the setInterval. Do it like this: function timer() { console.log("timer!"); } window.setInterval(timer, 1000); Or shorter (but when the function gets bigger also less readable): window.setInterval( function() { console.log(

Stop setInterval

阅读更多关于 Stop setInterval

问题 I want to stop this interval in the error handler from running repeatedly. Is that possible, and if so, how? // example code $(document).on(\'ready\',function(){ setInterval(updateDiv,3000); }); function updateDiv(){ $.ajax({ url: \'getContent.php\', success: function(data){ $(\'.square\').html(data); }, error: function(){ $.playSound(\'oneday.wav\'); $(\'.square\').html(\'<span style=\"color:red\">Connection problems</span>\'); // I want to stop it here } }); } 回答1: You need to set the

Code for a simple JavaScript countdown timer?

阅读更多关于 Code for a simple JavaScript countdown timer?

问题 I want to use a simple countdown timer starting at 30 seconds from when the function is run and ending at 0. No milliseconds. How can it be coded? 回答1: var count=30; var counter=setInterval(timer, 1000); //1000 will run it every 1 second function timer() { count=count-1; if (count <= 0) { clearInterval(counter); //counter ended, do something here return; } //Do code for showing the number of seconds here } To make the code for the timer appear in a paragraph (or anywhere else on the page),

Changing the interval of SetInterval while it's running

阅读更多关于 Changing the interval of SetInterval while it's running

问题 I have written a javascript function that uses setInterval to manipulate a string every tenth of a second for a certain number of iterations. function timer() { var section = document.getElementById(\'txt\').value; var len = section.length; var rands = new Array(); for (i=0; i<len; i++) { rands.push(Math.floor(Math.random()*len)); }; var counter = 0 var interval = setInterval(function() { var letters = section.split(\'\'); for (j=0; j < len; j++) { if (counter < rands[j]) { letters[j] = Math

Javascript setInterval and `this` solution

阅读更多关于 Javascript setInterval and `this` solution

问题 I need to access this from my setInterval handler prefs: null, startup : function() { // init prefs ... this.retrieve_rate(); this.intervalID = setInterval(this.retrieve_rate, this.INTERVAL); }, retrieve_rate : function() { var ajax = null; ajax = new XMLHttpRequest(); ajax.open(\'GET\', \'http://xyz.com\', true); ajax.onload = function() { // access prefs here } } How can I access this.prefs in ajax.onload ? 回答1: The setInterval line should look like this:- this.intervalID = setInterval(

setTimeout or setInterval?

阅读更多关于 setTimeout or setInterval?

问题 As far as I can tell, these two pieces of javascript behave the same way: Option A: function myTimeoutFunction() { doStuff(); setTimeout(myTimeoutFunction, 1000); } myTimeoutFunction(); Option B: function myTimeoutFunction() { doStuff(); } myTimeoutFunction(); setInterval(myTimeoutFunction, 1000); Is there any difference between using setTimeout and setInterval? 回答1: They essentially try to do the same thing, but the setInterval approach will be more accurate than the setTimeout approach,

Pass parameters in setInterval function

阅读更多关于 Pass parameters in setInterval function

Please advise how to pass parameters into a function called using setInterval . My example setInterval(funca(10,3), 500); is incorrect. You need to create an anonymous function so the actual function isn't executed right away. setInterval( function() { funca(10,3); }, 500 ); sbr now with ES5, bind method Function prototype : setInterval(funca.bind(null,10,3),500); Reference here Add them as parameters to setInterval: setInterval(funca, 500, 10, 3); The syntax in your question uses eval, which is not recommended practice. You can pass the parameter(s) as a property of the function object, not

Execute the setInterval function without delay the first time

阅读更多关于 Execute the setInterval function without delay the first time

问题 It\'s there a way to configure the setInterval method of javascript to execute the method immediately and then executes with the timer 回答1: It's simplest to just call the function yourself directly the first time: foo(); setInterval(foo, delay); However there are good reasons to avoid setInterval - in particular in some circumstances a whole load of setInterval events can arrive immediately after each other without any delay. Another reason is that if you want to stop the loop you have to

Calling a function every 60 seconds

阅读更多关于 Calling a function every 60 seconds

问题 Using setTimeout() it is possible to launch a function at a specified time: setTimeout(function, 60000); But what if I would like to launch the function multiple times? Every time a time interval passes, I would like to execute the function (every 60 seconds, let\'s say). 回答1: If you don't care if the code within the timer may take longer than your interval, use setInterval() : setInterval(function, delay) That fires the function passed in as first parameter over and over. A better approach

How can I make setInterval also work when a tab is inactive in Chrome?

阅读更多关于 How can I make setInterval also work when a tab is inactive in Chrome?

问题 I have a setInterval running a piece of code 30 times a second. This works great, however when I select another tab (so that the tab with my code becomes inactive), the setInterval is set to an idle state for some reason. I made this simplified test case (http://jsfiddle.net/7f6DX/3/): var $div = $(\'div\'); var a = 0; setInterval(function() { a++; $div.css(\"left\", a) }, 1000 / 30); If you run this code and then switch to another tab, wait a few seconds and go back, the animation continues