I have a text input and a textarea and I'm passing the value from the input to the textarea. I am trying to do, when you type something in the input and you stop, after 2 seconds show the values to the textarea.
In this example the textarea gets the input's value instantly:
http://jsfiddle.net/DXMG6/
So i want, when you type and stop, after 2 seconds give the value.
How can I achieve this? I tried to use setTimeout but when the 2 seconds pass, then it keeps getting the value instantly. So basically it works for the first 2 seconds.
You have to reset the timer everytime the user presses the key again:
jQuery(function($){
function changeFn(){
alert('Changed');
}
var timer;
$("#string").bind("keyup", function(){
clearTimeout(timer);
timer = setTimeout(changeFn, 2000)
});
});
Once i made this plugin called bindDelay for jQuery:
$.fn.bindDelay = function( eventType, eventData, handler, timer ) {
if ( $.isFunction(eventData) ) {
timer = handler;
handler = eventData;
}
timer = (typeof timer === "number") ? timer : 300;
var timeouts;
$(this).bind(eventType, function(event) {
var that = this;
clearTimeout(timeouts);
timeouts = setTimeout(function() {
handler.call(that, event);
}, timer);
});
};
Used like a normal bind method but the last argument is the delay before firing the handler (in mil sec):
$("input").bindDelay('keyup', function() {
$("textarea").text( $(this).val() );
}, 2000);
See fiddle: http://jsfiddle.net/c82Ye/2/
And you unbind and trigger it like normal:
$("input").unbind("keyup");
$("input").trigger("keyup");
setTimeout returns an ID of the "job". what you have to do is to clearTimeout(id) every type and setTimeout again:
var tID = null;
onclick() {
if (tID !== null) clearTimeout(tID);
tID = setTimeout(function() { /*Do domething*/ }, 2000);
}
What you need to do is set a timeout, and save the resulting timeout id. Then you need to check if the timeout id has been saved at each keypress. If the timeout is set, clear the timeout and reset it. Something like this:
var timeoutId = null;
var myFunc = function() {
timeoutId = null;
// Do stuff
};
var myEventHandler = function() {
if (timeoutId) {
window.clearTimeout(timeoutId);
}
timeoutId = window.setTimeout(myFunc, 2000);
};
...or check the updated fiddle:
http://jsfiddle.net/DXMG6/5/
I've updated your fiddle
This will update the textarea value 2 seconds after you end editing the text.
The relevant part is this: we keep a reference to a timeout, when the keyup event is fired we clear the previous timeout and we start a new timeout, that will fire in 2 seconds.
var timeout = null;
$("#string").on("keyup keypress paste mouseup", function () {
clearTimeout(timeout);
timeout = setTimeout(function() {
// ... your code here
}, 2000);
});
Try something like this. Use setTimeout, but each time a key is pressed, reset the timer and start over...
http://jsfiddle.net/DXMG6/10/
var textTimer=null;
$("#string").on("keyup keypress paste mouseup", function () {
if (textTimer) clearTimeout(textTimer);
textTimer = setTimeout(function(){
var a = $('#string').val();
$('#rdonly').html(a);
}, 2000);
});
$('.btn').click(function() {
$('#rdonly').text('');
$('#string').val('');
});
You just need to modify your code as follows:
var timeoutId = 0;
$("#string").on("keyup keypress paste mouseup", function () {
var a = $('#string').val();
// Cancel existing timeout, if applicable
if (timeoutId > 0) {
window.clearTimeout(timeoutId);
}
// Start a timeout for 2 seconds- this will be cancelled above
// if user continues typing
timeoutId = window.setTimeout(function () {
$('#rdonly').html(a);
}, 2000);
});
So I currently use something like:
$(window).resize(function(){resizedw();});
But this gets called many times while resizing process goes on. Is it possible to catch an event when it ends?
You can use setTimeout() and clearTimeout()
function resizedw(){
// Haven't resized in 100ms!
}
var doit;
window.onresize = function(){
clearTimeout(doit);
doit = setTimeout(resizedw, 100);
};
Code example on jsfiddle.
I had luck with the following recommendation: http://forum.jquery.com/topic/the-resizeend-event
Here's the code so you don't have to dig through his post's link & source:
var rtime;
var timeout = false;
var delta = 200;
$(window).resize(function() {
rtime = new Date();
if (timeout === false) {
timeout = true;
setTimeout(resizeend, delta);
}
});
function resizeend() {
if (new Date() - rtime < delta) {
setTimeout(resizeend, delta);
} else {
timeout = false;
alert('Done resizing');
}
}
Thanks sime.vidas for the code!
This is the code that I write according to #Mark Coleman answer:
$(window).resize(function() {
clearTimeout(window.resizedFinished);
window.resizedFinished = setTimeout(function(){
console.log('Resized finished.');
}, 250);
});
Thanks Mark!
Internet Explorer provides a resizeEnd event. Other browsers will trigger the resize event many times while you're resizing.
There are other great answers here that show how to use setTimeout and the .throttle, .debounce methods from lodash and underscore, so I will mention Ben Alman's throttle-debounce jQuery plugin which accomplishes what you're after.
Suppose you have this function that you want to trigger after a resize:
function onResize() {
console.log("Resize just happened!");
};
Throttle Example
In the following example, onResize() will only be called once every 250 milliseconds during a window resize.
$(window).resize( $.throttle( 250, onResize) );
Debounce Example
In the following example, onResize() will only be called once at the end of a window resizing action. This achieves the same result that #Mark presents in his answer.
$(window).resize( $.debounce( 250, onResize) );
There is an elegant solution using the Underscore.js So, if you are using it in your project you can do the following -
$( window ).resize( _.debounce( resizedw, 500 ) );
This should be enough :) But, If you are interested to read more on that, you can check my blog post - http://rifatnabi.com/post/detect-end-of-jquery-resize-event-using-underscore-debounce(deadlink)
There is a much simpler method to execute a function at the end of the resize than calculate the delta time between two calls, simply do it like this :
var resizeId;
$(window).resize(function() {
clearTimeout(resizeId);
resizeId = setTimeout(resizedEnded, 500);
});
function resizedEnded(){
...
}
And the equivalent for Angular2 :
private resizeId;
#HostListener('window:resize', ['$event'])
onResized(event: Event) {
clearTimeout(this.resizeId);
this.resizeId = setTimeout(() => {
// Your callback method here.
}, 500);
}
For the angular method, use the () => { } notation in the setTimeout to preserve the scope, otherwise you will not be able to make any function calls or use this.
One solution is extend jQuery with a function, e.g.: resized
$.fn.resized = function (callback, timeout) {
$(this).resize(function () {
var $this = $(this);
if ($this.data('resizeTimeout')) {
clearTimeout($this.data('resizeTimeout'));
}
$this.data('resizeTimeout', setTimeout(callback, timeout));
});
};
Sample usage:
$(window).resized(myHandler, 300);
You can store a reference id to any setInterval or setTimeout. Like this:
var loop = setInterval(func, 30);
// some time later clear the interval
clearInterval(loop);
To do this without a "global" variable you can add a local variable to the function itself. Ex:
$(window).resize(function() {
clearTimeout(this.id);
this.id = setTimeout(doneResizing, 500);
});
function doneResizing(){
$("body").append("<br/>done!");
}
You can use setTimeout() and clearTimeout() in conjunction with jQuery.data:
$(window).resize(function() {
clearTimeout($.data(this, 'resizeTimer'));
$.data(this, 'resizeTimer', setTimeout(function() {
//do something
alert("Haven't resized in 200ms!");
}, 200));
});
Update
I wrote an extension to enhance jQuery's default on (& bind)-event-handler. It attaches an event handler function for one or more events to the selected elements if the event was not triggered for a given interval. This is useful if you want to fire a callback only after a delay, like the resize event, or else.
https://github.com/yckart/jquery.unevent.js
;(function ($) {
var methods = { on: $.fn.on, bind: $.fn.bind };
$.each(methods, function(k){
$.fn[k] = function () {
var args = [].slice.call(arguments),
delay = args.pop(),
fn = args.pop(),
timer;
args.push(function () {
var self = this,
arg = arguments;
clearTimeout(timer);
timer = setTimeout(function(){
fn.apply(self, [].slice.call(arg));
}, delay);
});
return methods[k].apply(this, isNaN(delay) ? arguments : args);
};
});
}(jQuery));
Use it like any other on or bind-event handler, except that you can pass an extra parameter as a last:
$(window).on('resize', function(e) {
console.log(e.type + '-event was 200ms not triggered');
}, 200);
http://jsfiddle.net/ARTsinn/EqqHx/
Mark Coleman's answer is certainly far better than the selected answer, but if you want to avoid the global variable for the timeout ID (the doit variable in Mark's answer), you could do one of the following:
(1) Use a an immediately invoked function expression (IIFE) to create a closure.
$(window).resize((function() { // This function is immediately invoked
// and returns the closure function.
var timeoutId;
return function() {
clearTimeout(timeoutId);
timeoutId = setTimeout(function() {
timeoutId = null; // You could leave this line out.
// Code to execute on resize goes here.
}, 100);
};
})());
(2) Use a property of the event handler function.
$(window).resize(function() {
var thisFunction = arguments.callee;
clearTimeout(thisFunction.timeoutId);
thisFunction.timeoutId = setTimeout(function() {
thisFunction.timeoutId = null; // You could leave this line out.
// Code to execute on resize goes here.
}, 100);
});
This is what I use for delaying repeated actions, it can be called in multiple places in your code:
function debounce(func, wait, immediate) {
var timeout;
return function() {
var context = this, args = arguments;
var later = function() {
timeout = null;
if (!immediate) func.apply(context, args);
};
var callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) func.apply(context, args);
};
};
Usage:
$(window).resize(function () {
debounce(function() {
//...
}, 500);
});
ResizeStart and ResizeEnd events for window
http://jsfiddle.net/04fLy8t4/
I implemented a function which trigs two events on the user DOM element:
resizestart
resizeend
Code:
var resizeEventsTrigger = (function () {
function triggerResizeStart($el) {
$el.trigger('resizestart');
isStart = !isStart;
}
function triggerResizeEnd($el) {
clearTimeout(timeoutId);
timeoutId = setTimeout(function () {
$el.trigger('resizeend');
isStart = !isStart;
}, delay);
}
var isStart = true;
var delay = 200;
var timeoutId;
return function ($el) {
isStart ? triggerResizeStart($el) : triggerResizeEnd($el);
};
})();
$("#my").on('resizestart', function () {
console.log('resize start');
});
$("#my").on('resizeend', function () {
console.log('resize end');
});
window.onresize = function () {
resizeEventsTrigger( $("#my") );
};
This is a modification to Dolan's code above, I've added a feature which checks the window size at the start of the resize and compares it to the size at the end of the resize, if size is either bigger or smaller than the margin (eg. 1000) then it reloads.
var rtime = new Date(1, 1, 2000, 12,00,00);
var timeout = false;
var delta = 200;
var windowsize = $window.width();
var windowsizeInitial = $window.width();
$(window).on('resize',function() {
windowsize = $window.width();
rtime = new Date();
if (timeout === false) {
timeout = true;
setTimeout(resizeend, delta);
}
});
function resizeend() {
if (new Date() - rtime < delta) {
setTimeout(resizeend, delta);
return false;
} else {
if (windowsizeInitial > 1000 && windowsize > 1000 ) {
setTimeout(resizeend, delta);
return false;
}
if (windowsizeInitial < 1001 && windowsize < 1001 ) {
setTimeout(resizeend, delta);
return false;
} else {
timeout = false;
location.reload();
}
}
windowsizeInitial = $window.width();
return false;
}
Here is VERY simple script to trigger both a 'resizestart' and 'resizeend' event on the window object.
There is no need to muck around with dates and times.
The d variable represents the number of milliseconds between resize events before triggering the resize end event, you can play with this to change how sensitive the end event is.
To listen to these events all you need to do is:
resizestart: $(window).on('resizestart', function(event){console.log('Resize Start!');});
resizeend:
$(window).on('resizeend', function(event){console.log('Resize End!');});
(function ($) {
var d = 250, t = null, e = null, h, r = false;
h = function () {
r = false;
$(window).trigger('resizeend', e);
};
$(window).on('resize', function (event) {
e = event || e;
clearTimeout(t);
if (!r) {
$(window).trigger('resizestart', e);
r = true;
}
t = setTimeout(h, d);
});
}(jQuery));
i wrote a litte wrapper function on my own...
onResize = function(fn) {
if(!fn || typeof fn != 'function')
return 0;
var args = Array.prototype.slice.call(arguments, 1);
onResize.fnArr = onResize.fnArr || [];
onResize.fnArr.push([fn, args]);
onResize.loop = function() {
$.each(onResize.fnArr, function(index, fnWithArgs) {
fnWithArgs[0].apply(undefined, fnWithArgs[1]);
});
};
$(window).on('resize', function(e) {
window.clearTimeout(onResize.timeout);
onResize.timeout = window.setTimeout("onResize.loop();", 300);
});
};
Here is the usage:
var testFn = function(arg1, arg2) {
console.log('[testFn] arg1: '+arg1);
console.log('[testFn] arg2: '+arg2);
};
// document ready
$(function() {
onResize(testFn, 'argument1', 'argument2');
});
(function(){
var special = jQuery.event.special,
uid1 = 'D' + (+new Date()),
uid2 = 'D' + (+new Date() + 1);
special.resizestart = {
setup: function() {
var timer,
handler = function(evt) {
var _self = this,
_args = arguments;
if (timer) {
clearTimeout(timer);
} else {
evt.type = 'resizestart';
jQuery.event.handle.apply(_self, _args);
}
timer = setTimeout( function(){
timer = null;
}, special.resizestop.latency);
};
jQuery(this).bind('resize', handler).data(uid1, handler);
},
teardown: function(){
jQuery(this).unbind( 'resize', jQuery(this).data(uid1) );
}
};
special.resizestop = {
latency: 200,
setup: function() {
var timer,
handler = function(evt) {
var _self = this,
_args = arguments;
if (timer) {
clearTimeout(timer);
}
timer = setTimeout( function(){
timer = null;
evt.type = 'resizestop';
jQuery.event.handle.apply(_self, _args);
}, special.resizestop.latency);
};
jQuery(this).bind('resize', handler).data(uid2, handler);
},
teardown: function() {
jQuery(this).unbind( 'resize', jQuery(this).data(uid2) );
}
};
})();
$(window).bind('resizestop',function(){
//...
});
Well, as far as the window manager is concerned, each resize event is its own message, with a distinct beginning and end, so technically, every time the window is resized, it is the end.
Having said that, maybe you want to set a delay to your continuation? Here's an example.
var t = -1;
function doResize()
{
document.write('resize');
}
$(document).ready(function(){
$(window).resize(function(){
clearTimeout(t);
t = setTimeout(doResize, 1000);
});
});
I guess my case might be different from some others but I had a problem only with orientation change on iOS but wanted the resize event to run immediately. I used the ScreenOrientation API:
screen.orientation.addEventListener('change', (e) => {});
I took a slightly different tack and relied on mouseUp as the end of the resize event. trackSize is called on documentReady and the initial value of wide is set then, too.
var THRESHOLD = 784;
var TALL = 125, SHORT = 50;
var wide = (window.document.body.clientWidth >= THRESHOLD );
function trackSize() {
if( !wide ) {
setHeight( TALL );
} else {
setHeight( SHORT );
}
parent.window.addEventListener('resize', onResize);
}
function onResize(e) {
parent.window.removeEventListener('resize', onResize);
parent.window.addEventListener('mouseup', onMouseUp) ;
}
function onMouseUp(e) {
parent.window.removeEventListener('mouseup', onMouseUp);
wide = (window.document.body.clientWidth >= THRESHOLD);
trackSize();
}
After having set our window's initial height, we begin listening for a resize event. When it starts, we stop listening and start listening for the mouseUp event. Thus, we know that mouseUp will end the resizing. In mouseUp, we stop listening and set a toggle based on the window's width, then loop back to trackSize.
trackSize starts by setting the window's height based on the toggle -- if below the threshold, we increase height (because Bootstrap columns stack at small widths), otherwise set to standard. And then we listen again for the next resize event.
CAVEAT: This solution doesn't really work for resizing instantly using the maximize or restore window buttons. Maybe adding a test like isMouseDown and bypassing the mouse listener would suffice - I haven't yet tested that.
since the selected answer didn't actually work .. and if you're not using jquery here is a simple throttle function with an example of how to use it with window resizing
function throttle(end,delta) {
var base = this;
base.wait = false;
base.delta = 200;
base.end = end;
base.trigger = function(context) {
//only allow if we aren't waiting for another event
if ( !base.wait ) {
//signal we already have a resize event
base.wait = true;
//if we are trying to resize and we
setTimeout(function() {
//call the end function
if(base.end) base.end.call(context);
//reset the resize trigger
base.wait = false;
}, base.delta);
}
}
};
var windowResize = new throttle(function() {console.log('throttle resize');},200);
window.onresize = function(event) {
windowResize.trigger();
}
this worked for me as I did not want to use any plugins.
$(window).resize(function() {
var originalWindowSize = 0;
var currentWidth = 0;
var setFn = function () {
originalWindowSize = $(window).width();
};
var checkFn = function () {
setTimeout(function () {
currentWidth = $(window).width();
if (currentWidth === originalWindowSize) {
console.info("same? = yes")
// execute code
} else {
console.info("same? = no");
// do nothing
}
}, 500)
};
setFn();
checkFn();
});
On window re-size invoke "setFn" which gets width of window and save as "originalWindowSize". Then invoke "checkFn" which after 500ms (or your preference) gets the current window size, and compares the original to the current, if they are not the same, then the window is still being re-sized. Don't forget to remove console messages in production, and (optional) can make "setFn" self executing.
var resizeTimer;
$( window ).resize(function() {
if(resizeTimer){
clearTimeout(resizeTimer);
}
resizeTimer = setTimeout(function() {
//your code here
resizeTimer = null;
}, 200);
});
This worked for what I was trying to do in chrome. This won't fire the callback until 200ms after last resize event.
UPDATE!
Better alternative also created by me is here:
https://stackoverflow.com/a/23692008/2829600
(supports "delete functions")
ORIGINAL POST:
I wrote this simple function for handling delay in execution, useful inside jQuery .scroll() and .resize() So callback_f will run only once for specific id string.
function delay_exec( id, wait_time, callback_f ){
// IF WAIT TIME IS NOT ENTERED IN FUNCTION CALL,
// SET IT TO DEFAULT VALUE: 0.5 SECOND
if( typeof wait_time === "undefined" )
wait_time = 500;
// CREATE GLOBAL ARRAY(IF ITS NOT ALREADY CREATED)
// WHERE WE STORE CURRENTLY RUNNING setTimeout() FUNCTION FOR THIS ID
if( typeof window['delay_exec'] === "undefined" )
window['delay_exec'] = [];
// RESET CURRENTLY RUNNING setTimeout() FUNCTION FOR THIS ID,
// SO IN THAT WAY WE ARE SURE THAT callback_f WILL RUN ONLY ONE TIME
// ( ON LATEST CALL ON delay_exec FUNCTION WITH SAME ID )
if( typeof window['delay_exec'][id] !== "undefined" )
clearTimeout( window['delay_exec'][id] );
// SET NEW TIMEOUT AND EXECUTE callback_f WHEN wait_time EXPIRES,
// BUT ONLY IF THERE ISNT ANY MORE FUTURE CALLS ( IN wait_time PERIOD )
// TO delay_exec FUNCTION WITH SAME ID AS CURRENT ONE
window['delay_exec'][id] = setTimeout( callback_f , wait_time );
}
// USAGE
jQuery(window).resize(function() {
delay_exec('test1', 1000, function(){
console.log('1st call to delay "test1" successfully executed!');
});
delay_exec('test1', 1000, function(){
console.log('2nd call to delay "test1" successfully executed!');
});
delay_exec('test1', 1000, function(){
console.log('3rd call to delay "test1" successfully executed!');
});
delay_exec('test2', 1000, function(){
console.log('1st call to delay "test2" successfully executed!');
});
delay_exec('test3', 1000, function(){
console.log('1st call to delay "test3" successfully executed!');
});
});
/* RESULT
3rd call to delay "test1" successfully executed!
1st call to delay "test2" successfully executed!
1st call to delay "test3" successfully executed!
*/
var flag=true;
var timeloop;
$(window).resize(function(){
rtime=new Date();
if(flag){
flag=false;
timeloop=setInterval(function(){
if(new Date()-rtime>100)
myAction();
},100);
}
})
function myAction(){
clearInterval(timeloop);
flag=true;
//any other code...
}
I don't know is my code work for other but it's really do a great job for me. I got this idea by analyzing Dolan Antenucci code because his version is not work for me and I really hope it'll be helpful to someone.
var tranStatus = false;
$(window).resizeend(200, function(){
$(".cat-name, .category").removeAttr("style");
//clearTimeout(homeResize);
$("*").one("webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend",function(event) {
tranStatus = true;
});
processResize();
});
function processResize(){
homeResize = setInterval(function(){
if(tranStatus===false){
console.log("not yet");
$("*").one("webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend",function(event) {
tranStatus = true;
});
}else{
text_height();
clearInterval(homeResize);
}
},200);
}
I wrote a function that passes a function when wrapped in any resize event. It uses an interval so that the resize even isn't constantly creating timeout events. This allows it to perform independently of the resize event other than a log entry that should be removed in production.
https://github.com/UniWrighte/resizeOnEnd/blob/master/resizeOnEnd.js
$(window).resize(function(){
//call to resizeEnd function to execute function on resize end.
//can be passed as function name or anonymous function
resizeEnd(function(){
});
});
//global variables for reference outside of interval
var interval = null;
var width = $(window).width();
var numi = 0; //can be removed in production
function resizeEnd(functionCall){
//check for null interval
if(!interval){
//set to new interval
interval = setInterval(function(){
//get width to compare
width2 = $(window).width();
//if stored width equals new width
if(width === width2){
//clear interval, set to null, and call passed function
clearInterval(interval);
interval = null; //precaution
functionCall();
}
//set width to compare on next interval after half a second
width = $(window).width();
}, 500);
}else{
//logging that should be removed in production
console.log("function call " + numi++ + " and inteval set skipped");
}
}
I have a website which I would like to auto refresh ONLY if user is not using it for a specific time (ie.180 sec).Is there a way to auto refresh HTML only if there has been no activity on a page?
Thank you!
Two approaches:
1. Use a once-a-second timer and a "timeout" value.
You probably want to wrap this up in an object:
var activityHandler = (function() {
var timerHandle = 0,
timeout;
flagActivity();
function start() {
stop();
flagActivity();
timerHandle = setInterval(tick, 1000);
}
function stop() {
if (timerHandle != 0) {
clearInterval(timerHandle);
timerHandle = 0;
}
}
function flagActivity() {
timeout = new Date() + 180000;
}
function tick() {
if (new Date() > timeout) {
stop();
location.reload();
}
}
return {
start: start,
stop: stop,
flagActivity: flagActivity
};
})();
Then start it on page load:
activityHandler.start();
And ping it every time you see "activity":
activityHandler.flagActivity();
So for instance, you might do this:
if (document.addEventListener) {
document.addEventListener('mousemove', activityHandler.flagActivity, false);
}
else if (document.attachEvent) {
document.attachEvent('onmousemove', activityHandler.flagActivity);
}
else {
document.onmousemove = activityHandler.flagActivity;
}
2. Use a timer you reset every time there's "activity".
This is less ongoing work (we don't have something happening every second), but more work when you flag that activity has happened.
Set up a timer to do the refresh:
var handle = setTimeout(function() {
location.reload();
}, 180000);
...and then cancel and reschedule any time you see whatever you consider to be "activity":
clearTimeout(handle);
handle = setTimeout(...);
You can wrap this up in a function:
var inactivityTimerReset = (function() {
var handle = 0;
function reset() {
if (handle != 0) {
clearTimeout(handle);
}
handle = setTimeout(tick, 180000);
}
function tick() {
location.reload();
}
return reset;
})();
// Kick start
inactivityTimerReset();
// ...and anywhere you see what you consider to be activity, call it
// again
inactivityTimerReset();
Then, again, ping it on every activity. But this is a lot more work than I'd put in a mousemove handler, hence solution #1 above.
var docTimeOut;
function bodyTimeOut()
{
docTimeOut=setTimeout(function(){location.reload();},18000);
}
function resetTimeOut()
{
clearTimeout(docTimeOut);
bodyTimeOut();
}
document.onload = bodyTimeOut;
document.body.onmouseover= resetTimeOut;
you could declare a variable pageActive or something, set it to false, and whenever user does something set it to true.
Then, set a function to execute periodically as frequently as you want with setinterval() that checks this variable, if it's true set it to false to start again, if is false then refresh page.
You can use onblur and onfocus on body element to see if there is a kind of activity on your page.