Local storage being read too many times - javascript

I am trying to write the values of checkboxes to local storage and then retrieve them. Setting the values works fine. However, when I try to access local storage it accesses it too many times and the number of times it accesses it increments each time the function is called. For example, the first time the function is called a single array is printed to the console. The second time 2 arrays are printed, the third time three arrays are printed and so on.
My subsequent code goes on to display the items from the array in an HTML list, therefore, having multiple arrays confuses it and duplicates the data
Any clue how I can prevent the array from being generated multiple times?
I have attempted to remove the for loop to see if that is the cause but this makes no difference. As far as I am aware it is a problem with the first part but I am not too sure where
$("#confirm-button").click(function(event){
event.preventDefault();
if (localStorage.length===0) {
createAlbum();
}
else if (localStorage.length>0) {
document.getElementById("confirmation").style.display="block";
$("#Yes").click(function(event){
event.preventDefault();
localStorage.clear();
createAlbum();
document.getElementById("confirmation").style.display="none";
})
$("#No").click(function(event){
event.preventDefault();
document.getElementById("confirmation").style.display="none";
})
}
});
function createAlbum(){
if ($("li input:checkbox:checked").length===0){
alert("You have not selected any songs. Please select at least one song")
}
else if ($("li input:checkbox:checked").length>0) {
var searchIDs = $("li input:checkbox:checked").map(function () {
return $(this).val();
}).get();
localStorage.setItem('searchIDs', JSON.stringify(searchIDs));
retrievedObject = localStorage.getItem('searchIDs');
var information = JSON.parse(retrievedObject);
console.log(information);
$('#overlay_text').append("<ol id='newList'></ol>");
for (var i = 0; i < information.length; i++) {
var item = document.createElement('li');
item.append(information[i]);
$('#newList').append(item);
}
}
}
HTML:
<div id="overlay">
<div id="overlay_text">
</div>
</div>
<div id="confirmation">
<div id="confirmation-text">
An album already exists are you sure you want to overwrite it?
<button id="Yes">Yes</button>
<button id="No">No</button>
</div>
</div>
EDIT
Included the code that calls the function. The first bit is to check if any values currently exist in local storage. If no values exist the function is called. If values do exist the user is then asked if they wish to overwrite this data. 'confirmation' is the window that displays the message about overwriting data to the user

I suspect your problem is a result of creating event listeners inside the handler of another event. This is a bad practice in general
Every time the confirm button is clicked you add a new listener to the Yes/No buttons and thus the event handlers for Yes/No are getting called multiple times (once for every time user clicks on confirm)
Move your Yes/No click listeners outside of $("#confirm-button").click or use off() before adding a new click
$("#Yes").off('click').on('click', function(event){...

This is happening because you are adding the events every time when a user clicks on the confirm-button try moving the functions $("#Yes").click(function(event) and $("#No").click(function(event) out of the $("#confirm-button").click(function(event).

Related

Delete a single URL from a chrome-extension popup-window seems not working with adding event listeners (the event listener might be scoped?)

Background information
I am trying to make a functional chrome-extension popup-window that enables the user to add links (based on the open tab's URL) when he desires it, and deletes one link or delete all of the links in just one click. Down below are all of my files! I must say in advance that I am not very good (and not experienced) with using jQuery's library but if that's the only solution that I have, than I will use it in my code.
The problem
The buttons to delete all the links and the button to add one link does work perfectly without bugs. However, the button to which one link should be deleted doesn't work, I tried various ways including splicing. I am trying to remove the link from the DOM and from the chrome.storage.local, both actions do not work. In the following code you can see all of the files I have thus far. The code of when the 'X' button is pressed doesn't get executed (see these pictures): https://i.stack.imgur.com/gg1Dy.png and https://i.stack.imgur.com/4oGdI.png
The code
manifest.json:
gist.github.com/kobrajunior/78acda830c2d1c384333542422f1494d
popup.js:
functions to look at: addToDom and removeMe and the very first event listener when the DOM is fully loaded
gist.github.com/kobrajunior/4852f85ae18cfb9edbe542a820b8c107
For extra information (if needed), the popup.html:
gist.github.com/kobrajunior/1c26691734c19391c62dc336ed2e1791
Thank you in advance.
For the following lines in popup.js, you want to restore (show all the items/buttons) and bind listeners, however don't forget addToDom is called inside the callback of chrome.storage.local.get, that means by the time you assign value to allButtons, they're not added to DOM, that causes allButtons.length === 0 and you didn't bind anything in fact.
Try to move the binding logic inside the callback of restore (You may encounter other issues however that's not covered in this quesions).
document.addEventListener('DOMContentLoaded', function () {
restore();
var allButtons = document.getElementsByClassName('buttons');
function listenI(i) {
allButtons[i].addEventListener('click', () => removeMe(i));
}
for (var i = 0; i < allButtons.length; i++) {
listenI(i);
}
});
function restore() {
// get the tab link and title
chrome.storage.local.get({ urlList: [], titleList: [] }, function (data) {
urlList = data.urlList;
titleList = data.titleList;
// add the titles and url's to the DOM
for (var i = 0, n = urlList.length; i < n; i++) {
addToDom(urlList[i], titleList[i]);
}
});
}

why do my onClick functions take two clicks

I've noticed from a few different projects of mine that whenever I click something I add an onClick function to, it always takes two clicks to get them going when a page is freshly loaded. The general structure I use for them is:
function PageChange(){
var welc_p = document.getElementById("welcome");/**gathers page DIVs**/
var page01 = document.getElementById("page01");
var page02 = document.getElementById("page02");
var start = document.getElementById("start_btn");/**gathers buttons**/
var p1_back = document.getElementById("p1_back");
var p1_next = document.getElementById("p1_back");
var p2_back = document.getElementById("p2_back");
var p2_next = document.getElementById("p2_back");
start.onclick=function(){
page01.style.display="block";
welc_p.style.display="none";
window.location="#page01";
};
}/**function**/
then the way I call it in the html is
<div class="some_class" id="start_btn" onClick="PageChange()">!!!LETS GET STARTED!!!</div>
Here's a fiddle of it as well.
https://jsfiddle.net/Optiq/42e3juta/
this is generally how I structure it each time I want to create this functionality. I've seen tons of other posts on here about their items taking 2 clicks to activate but none of them were doing anything near what I was trying to accomplish and it seemed their problem was within their coding. Does anybody know why this is happening?
This is because you are attatching a event handler to your button on click of your button.
This means that one click of the button activates the event handler, not the code within start.onclick=function() {
Then, the second click works becasue the event handler has been activated, and now the code will run.
Try moving your code out of the function, then it will work with just one click
Just had the same issue, and found an easy solution based on the above answer.
Since your function needs two clicks to work, I just called the function above the function and it works fine. This way the function already gets called one time on load, then it gets called the second time when you click it.
yourFunction();
function yourFunction(){
-- content --
}
I also had the same 2 clicks required on intitial interaction and after many searches couldn't find the best solution for my specific nav menu. I tried this solution above but couldn't get it to work.
Stumbled upon this code from a youtube example and it solved my issue. I wanted to nest submenu's for multiple levels and modified it from its original implementation to work best for my responsive mobile menu.
var a;
function toggleFirstLevelMobileSubMenu(){
if(a==1){
document.getElementById("mobile-sub-menu-depth-1").style.display="none";
return a=0;
}
else {
document.getElementById("mobile-sub-menu-depth-1").style.display="flex";
return a=1;
}
}
var b;
function toggleSecondLevelMobileSubMenu(){
if(b==1){
document.getElementById("mobile-sub-menu-depth-2").style.display="none";
return b=0;
}
else {
document.getElementById("mobile-sub-menu-depth-2").style.display="flex";
return b=1;
}
}
Of course, in the CSS I had display: none set for both ID's.
First, the problem:- On first click instead of running js your browser runs the button aka the event.
Solution:- in order to resolve this we need to make sure our function is already before the event is run (this is one of the ways to solve the problem). To achive this we need to load the function aka call the function in some way.
So, i just simply called the function after function is completed.
Code answer-
Just add at the end of your code
PageChange();

jQuery functions run in background?

I have a page with a lot of elements (~1,500) of the same class on it, and when I execute
$(".pickrow").addClass("vis");
it takes a second or two for the page to reflect the changes. So that users aren't thinking the page was stuck, I'd like to pop-up a small message using:
$("#msgDiv").show();
$(".pickrow").addClass("vis");
$("#msgDiv").hide();
But the msgDiv never shows. If I remove the $("#msgDiv").hide(); the msgDiv appears simultaneously with the application of the added class (after the 1 or 2 seconds it took to add the class).
It seems like the jQuery functions get pooled and run together without any screen updates until they have all completed.
How can I get the msgDiv to appear while the $(".pickrow").addClass("vis"); is processing?
Here's a Demo
You probably want to delay the hide by a few seconds.
$("#msgDiv").show();
$(".pickrow").addClass("vis");
setTimeout(function(){ $("#msgDiv").hide(); },2000);
Or using jQuery's animations queue for timing:
$("#msgDiv").show();
$(".pickrow").addClass("vis");
$("#msgDiv").delay(2000).hide(1); //must make it at least 1 ms to go into the queue
You can go with this approach also
Working DEMO
$(document).on("click",".btn",function(){
$(".msg").show("fast",function(){
$(".pickrow").addClass("vis");
var interval = setInterval(function(){
var picLength = $(".pickrow").length;
var visLength = $(".vis").length;
if(picLength == visLength){
clearInterval(interval);
$(".msg").hide();
}
},500);
});
});
I think if you simplify the code, you would find that it is much more responsive and probably not require the loading message. In your code, you check every single element in an if statement. Rather than do that, you can check one value, then update all of them accordingly.
Here's a demo: http://jsfiddle.net/jme11/3A4qU/
I made a single change to your HTML to set the initial value of the input button to "Show Details". Then in the following code, you can just check whether the value is Show Details and remove the class that hides the .pickrow and update the value of the button to be "Hide Details" (which is better feedback for the user anyway). Likewise, you can add the .hid class to the pickrow if the button value is not "Show Details". This will also normalize all of the classes regardless if some were individually hidden or shown.
$('#showhide').on('click', function(){
if ($(this).val() === 'Show Details') {
$('.pickrow').removeClass('hid');
$(this).val('Hide Details');
} else {
$('.pickrow').addClass('hid');
$(this).val('Show Details');
}
});

jQuery JavaScript : How to keep track of actions done by users?

I have a webpage with images.
A user can click on images to show() or hyde() these images.
Sometimes, the user opens a popup to watch a video.
Then the code hide() all elements previously opened.
When the user closes the video, i need to know which elements was previously opened in order to show only them.
What is the best way to do that ?
What i've done :
I've created an array and i push images names into it.
var arr_popup_open = [];
Then, this function is called when user open a popup and hide all elements :
function toggleAllPopup() {
if( $('#popup_micro_1').is(":visible"))
{
$('#popup_micro_1').hide();
arr_popup_open.push('#popup_micro_1');
}
if( $('#popup_micro_2').is(":visible"))
{
$('#popup_micro_2').hide();
arr_popup_open.push('#popup_micro_2');
}
if( $('#popup_micro_3').is(":visible"))
{
$('#popup_micro_3').hide();
arr_popup_open.push('#popup_micro_3');
}
}
// and so on ... I have 7 images so it seems it's not very well optimized
When i need to show only images previously opened, i execute this code, a loop to show() elements in array.
$('#close_pop_up').click(function() {
for(var i= 0; i < arr_popup_open.length; i++)
{
$(arr_popup_open[i]).show();
}
});
What do you think about that ? Is there a better way to to do it ?
There are a few ways you could go about this with jQuery. Your way should work, but if you want to reduce the amount of code you could do something like:
var visibleDivs = $('div:visible', '#ContainerDiv');
Alternatively you could add a specific class to all visible elements when you show them and use:
var visibleDivs = $('.someClassName');
When hiding them due to your popup, you can store the list in the data of any element. In this case, putting it on #close_pop_up might make sense:
visibleDivs.hide();
$('#close_pop_up').data('myDivs', visibleDivs);
When you want to show them again in your click function:
$('#close_pop_up').click(function() {
$(this).data('myDivs').show();
});
Looks fine to me. Just remember to clear arr_popup_open in the start of the toggleopen function.
The alternative you could do if you really wanted is to keep the information of what is open or closed in Javascript variables that get updated when you open and close things. This way you don't need to depend on complex things such as is(:visible)

how to alert user when there are changes inside an object field

how can i alert the user if there are any changes inside the object field
i''m trying to detect the changes on this div inside the object
if it's normal the code would be this:
<div id="HeaderNewMessageIcon" class="BrosixContactNewMessage" style="display:none;">
</div>
but if there are changes it will look like this:
<div id="HeaderNewMessageIcon" class="BrosixContactNewMessage" style="display: block; ">
</div>
i want to alert the user if there are changes inside the object, either via alert or using an image.
is there any way for me to achieve this?
and another thing, i have no access to the code inside the object, i can only view it but not edit it.
I believe there must be some JavaScript code which changing your html you can call your method from there. Other way you can use setInterval.
You can use jQuery plugin Mutation Events plugin for jQuery . see thread
var a = document.getElementsByClassName('HeaderNewMessageIcon')[0];
var oldTitle = a.title;
setInterval(function(){
if(a.title !== oldTitle){
alert("Title change");
oldTitle = a.title;
}
},100);
jsfiddle
You have to detect the changes when throught user interaction such as click, mouseover, mousedown, etc... then you can attach a function to see if its attributes or anything inside it changes.
//detect inputs change
$('#HeaderNewMessageIcon').find(':input').change(function(){ alert(...)});
//detect attributes change
$('#HeaderNewMessageIcon').click(function(){
detectChange(this);
});
As for detectChange to work, you must save the attributes when page just loaded
var attrs = $('#HeaderNewMessageIcon').get(0).attributes;
function detectChange(obj){
//pseudo-code, you need to find a function on the web to commpare 2 objetcs
if (obj.attributes === attrs){
alert(...);
}
//the same comparison for the children elements $(obj).children()
}

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