We Keep Coding

Fire javascript every x page load, for example, every 3rd page

I'm sure this question has been answered, before, but my searches are coming up empty.
I have a simple jQuery function (that slides in a box after the page has been scrolled down). It works fine.
However, how do I set cookies, or other method, to make it execute on the first page load and, then, on every 3rd page load of the session, after that?

A little snippet like this should work for you.
(function () {
// Get the countdown from localStorage
var countdown = Number(window.localStorage.getItem('countdown'));
// If countdown isn’t set it or if it has
// run a couple times it’ll be `0`
// Either way—we reset countdown and run the function
if (!countdown) {
countdown = 3;
// Run the function
}
// Update the countdown
window.localStorage.setItem('countdown', countdown - 1);
})();

These are both very instructive answers (my javascript skill is at the piece-it-together level). If it's helpful to someone, even though the question was for a javascript solution, I realized there might be a PHP solution, as well.
This worked, too:
<?php //Slide-in ad will show every x pages
$slide_ad_frequency=3;
session_start();
//increase the already-set counter by 1 or initiate the counter with a value of 1
if( isset( $_SESSION['counter'] ) )
{
$_SESSION['counter'] += 1;
}
else
{
$_SESSION['counter'] = 1;
}
//If counter equals the ad frequency setting
if($_SESSION['counter'] % $slide_ad_frequency == 0) : ?>
... Code to execute ...
<?php endif ?>

You can store the count of window loads on the sessionStorage so that data won't be lost on every reload. The data will be cleared when the tab is closed. If you want your data to not expire when the session ends, you should instead use localStorage; both have the same implementation.
window.onload = doSomething;
function doSomething() {
let count = sessionStorage.getItem('noOfPageLoads');
if( count ) { //if count is not null, increment it
count++;
sessionStorage.setItem('noOfPageLoads', count); //update the local storage
}
else { //if count is null, it's the first load, so put it in the local storage
count = 0;
sessionStorage.setItem('noOfPageLoads', count);
}
console.log('noOfPageLoads = '+ count)
if( count===0 || count===3 ) {
console.log('do something now');
//do what you want here
}
}

How to add TimeOut to current slider code?

I'm doing an easy slider with buttons, it works fine, but I'd like to add TimeOut() function to current code, to allow slides to change automatically.
I tried to do that with jQuery but it didn't work.
$('.reviews-slider-button').click(function() {
var i = $(this).index();
$('.reviews-slider-person').hide();
$('.reviews-slider-person-' + (i + 1)).show();
});
I'd like to change automatically slider every 10 seconds, and when I would click on .reviews-slider-button it would reset the timer ( to avoid situation I click to change slide, and timer automatically change to the next one).
I'd be grateful for your advice's.

You can use setInterval to click your button every 10 seconds:
var timer = ''; // Make global variable
function ScrollAuto() {
temp = setInterval(function() {
$('.nextButton').click();
}, 10000)
return timer;
}
And to reset your timer, inside your reset button add:
clearInterval(timer);

Similarly to the answer from Shree, but make it cleaner, but use timeout, not interval, you want the system to change slide every 10 seconds unless you click, in which case you reset the timeout, go to the next slide, and set up the next timeout
Something like this:
var slideMaxDuration = 10000; // in ms
var slideTimer = void 0;
function nextSlide() {
clearInterval(slideTimer);
// ... go to next slide ...
}
function autoContinue() {
nextSlide();
setTimeout(autoContinue, slideMaxDuration);
}
$('.reviews-slider-button').click(autoContinue);
You also need to set up the initial autoContinue when you want the whole thing to start.

setTimeout executes itself right away/on clear

I'm making a webpage where user events are logged in.
To test the feature I made a small, independant webpage with a teaxtarea and a text input. The events logged are those performed on the input element.
I want to prevent the same event text to be shown multiple times in a row, but I can't seem to prevent them from showing up!
I also want to add a line to separate event groups 0.5 seconds after no other event happened, but the line seems to appear on every event trigger, evenif I use clearTimeout with the timeout ID.
Basically: I don't want any line to be repeated. If the last line is a separator line, then it must not add another one. Yet it doesn't see to work.
JSFiddle Demo
Here is my code:
JavaScript
var timerID = 0;
function addSeparateLine()
{
document.getElementById('listeEvenements').value += "--------------------\n";
}
function show(newEventText)
{
var eventListField = document.getElementById('listeEvenements');
var eventList = [];
if (eventListField.value.length > 0)
{
eventList = eventListField.value.split("\n");
}
var eventCounter = eventList.length;
if (eventList[eventCounter - 2] == newEventText)
{
clearTimeout(timerID);
newEventText = "";
}
timerID = setTimeout(addSeparateLine, 500);
if (newEventText !== "")
{
eventListField.value += newEventText + "\n";
}
return true;
}
HTML
<fieldset id="conteneurLogEvenements">
<legend>Events called from HTML attribute</legend>
<textarea id="listeEvenements" rows="25"></textarea>
<input id="controleEcoute" type="text" onBlur="show('Blur');" onchange="show('Change');" onclick="show('Click');" onfocus="show('Focus');" onMousedown="show('MouseDown');" onMousemove="show('MouseMove');" onMouseover="show('MouseOver');" onkeydown="show('KeyDown');"
onkeypress="show('KeyPress');" onkeyup="show('KeyUp');" />
</fieldset>
http://jsfiddle.net/z6kb4/2/

It sounds like what you want is a line that prints after 500 milliseconds of inactivity, but what your code currently says to do is "print a line 500 milliseconds after any action, unless it gets canceled". You can get better results by structuring the code more closely to your intended goal.
Specifically, instead of scheduling a new timeout every time an event occurs, simply start a loop when the first event occurs that checks the time that has elapsed since the most recent event received and then prints a line when the elapsed time exceeds the desired threshold (500 milliseconds). Something like:
function addSeparateLine() {
var elapsed = new Date().getTime() - lastEventTime;
if (elapsed >= 500) {
document.getElementById('listeEvenements').value += "--------------------\n";
clearInterval(timerID);
timerID = -1;
}
}
...and then you schedule it like:
if(newEventText !== "") {
lastEventTime = new Date().getTime();
eventListField.value += newEventText+"\n";
if (timerID == -1) {
timerID = setInterval(addSeparateLine,100);
}
}
Working example here: http://jsfiddle.net/z6kb4/4/

Because you are not actually stopping the show function in any way. The clearTimeout only applies to the separator add. I have updated your fiddle. You need to wrap your function with
if (+new Date() - lastfire < 500) return;
and
lastfire = +new Date();
(before the last return--see the updated fiddle). Also, make sure to stick the global definition var lastfire = -1; somewhere up top.

Greasemonkey popup loop not waiting for load-event listener

I'm writing a Greasemonkey script to automatically delete my notifications from a site, based on words I enter into a search box.
The delete "button" is basically a link, so I'm trying to open the first link in a new tab. Then, after it loads enough, open the rest of the links, one by one, in that same tab.
I figured out how to get the links I needed and how to loop and manipulate them. I was able to grab the first delete-link and open it in a new tab. I added an event listener to make sure the page was loaded before going to the next link.
I finally made that work so added my search box and button. Then I had to figure out how to wrap the whole thing in the event listener again.
So, I now have the whole thing working, except only the last link loads.
All links are going to my waitFor function so they should open, so it seems the event listener isn't working so it goes through the loop too fast and only the last link loads.
How do I make this script not continue the loop until the previous loaded page is fully loaded?
Complete code except for box and button creation:
var mytable = document.getElementById ('content').getElementsByTagName ('table')[0]
var myrows = mytable.rows
//function openLinkInTab () {
//mywin2.close ();
//}
var mywin2;
mywin2 = window.open ("http://www.aywas.com/message/notices/test/", "my_win2");
var links;
var waitFor = function (i) {
links = myrows[i].cells[1].getElementsByTagName ("a");
mywin2 = window.open (links[0].href, "my_win2");
}
var delnotifs = function () {
var matching;
var toRemove;
toRemove = document.getElementById ('find').value;
alert (toRemove)
for (i = 0; i < 10; i++) {
matching = myrows[i].cells[0].innerHTML;
if (matching.indexOf (toRemove) > 0) {
mywin2.addEventListener ('load', waitFor (i), false);
}
}
}
searchButton.addEventListener ('click', delnotifs, true);
So, why isn't it waiting for `mywin2.addEventListener('load', waitFor(i), false);`? I have a feeling it's something extremely simple that I'm missing here, but I just can't see it.
I also tried mywin2.addEventListener('load', function(){waitFor(i)}, false); and it still does the same thing, so it's not a problem of being a call instead of a pointer.
Swapping mywin2.addEventListener('load', waitFor(i), false); for
if (mywin2.document.readyState === "complete") { waitFor(i)} doesn't work either.
And while I'm at it... every time I see code looping through a list like this it uses
for(i=1;i < myrows.length;i++)
Which was skipping the first link in the list since arrays start at zero. So my question is, if I switch 'i' to zero, and the loop only goes while 'i' is < length, doesn't that mean it won't go through the whole list? Shouldn't it be
for(i=0;i != myrows.length;i++)

When you open a popup (or tab) with window.open, the load event only fires once -- even if you "open" a new URL with the same window handle.
To get the load listener to fire every time, you must close the window after each URL, and open a new one for the next URL.
Because popups are asynchronous and you want to load these links sequentially, don't use a for() loop for that. Use the popup load status to "chain" the links.
Here is the code to do that. It pushes the links onto an array, and then uses the load event to grab and open the next link. You can see the code in action at jsFiddle. :
var searchButton = document.getElementById ('gmPopUpBtn');
var mytable = document.getElementById ('content').getElementsByTagName ('table')[0];
var myrows = mytable.rows;
var linksToOpen = [];
var mywin2 = null;
function delnotifs () {
var toRemove = document.getElementById ('find').value;
for (var J = 0, L = myrows.length; J < L; J++) {
var matching = myrows[J].cells[0].innerHTML;
if (matching.indexOf (toRemove) > 0) {
var links = myrows[J].cells[1].getElementsByTagName ("a");
linksToOpen.push (links[0].href); //-- Add URL to list
}
}
openLinksInSequence ();
};
function openLinksInSequence () {
if (mywin2) {
mywin2.close ();
mywin2 = null;
}
if (linksToOpen.length) {
var link = linksToOpen.shift ();
mywin2 = window.open (link, "my_win2");
mywin2.addEventListener ('load', openLinksInSequence, false);
}
}
searchButton.addEventListener ('click', delnotifs, true);

See https://developer.mozilla.org/en-US/docs/Web/API/EventTarget.addEventListener.
The second argument of the addEventLister function must be a pointer to a function and not a call.

Calculating the time between two clicks in Javascript

I want to calculate the time between two clicks of an attribute with javascript but I don't know how.
For example;
click here
if the user clicks more than once -let's say in 5 seconds- I want to display an alert. I'm using jQuery if that helps. I don't know much about javascript but I've been coding a small project in my free time.

Something like this would do the trick. Keep a variable with the time of the last click and then compare it when the user clicks the link again. If the difference is < 5 seconds show the alert
<a id='testLink' href="#">click here</a>
<script type='text/javascript'>
var lastClick = 0;
$("#testLink").click(function() {
var d = new Date();
var t = d.getTime();
if(t - lastClick < 5000) {
alert("LESS THAN 5 SECONDS!!!");
}
lastClick = t;
});
</script>

The following may help you getting started:
var lastClicked = 0;
function onClickCheck() {
var timeNow = (new Date()).getTime();
if (timeNow > (lastClicked + 5000)) {
// Execute the link action
}
else {
alert('Please wait at least 5 seconds between clicks!');
}
lastClicked = timeNow;
}
HTML:
click here

Create a variable to hold the time of a click, say lastClick.
Set up a click handler for the element you want to track clicks on.
Inside the handler, check for a value in lastClick. If there is no value, set it to the current time. If there is a value, compare it against the current time. If the difference is within the range you're checking for, display the alert.

Start with
var lastClicked = (new Date()).getTime(); //not zero