Develop Reference

changing Div order in a div main container, javascript DOM manipulation

i want to move a div form the start to the end in a the same div:from 1-2-3 to 2-3-1
my code
const cards = document.querySelectorAll(".card");
const firstCard = document.querySelectorAll(".card")[0].innerHTML;
cards[0].remove();
document.getElementById("mainC").appendChild(firstCard);
<div id="mainC">
<div class="card"> 1 </div>
<div class="card"> 2 </div>
<div class="card"> 3 </div>
</div>
i want to move a div form the start to the end in a the same div:from 1-2-3 to 2-3-1

Based on your original code,we need to remove .innerHTML,then it will work
const cards = document.querySelectorAll(".card");
const firstCard = document.querySelectorAll(".card")[0];// remove .innerHTML and it will work
cards[0].remove();
document.getElementById("mainC").appendChild(firstCard);
<div id="mainC">
<div class="card"> 1 </div>
<div class="card"> 2 </div>
<div class="card"> 3 </div>
</div>
Another solution is to store the content into an array and change the array element order
let divs = []
document.querySelectorAll('#mainC .card').forEach(d =>{
divs.push(d.outerHTML)
})
divs.push(divs.shift())
document.querySelector('#mainC').innerHTML = divs.join('')
<div id="mainC">
<div class="card"> 1 </div>
<div class="card"> 2 </div>
<div class="card"> 3 </div>
</div>

you have used document.querySelectorAll(".card")[0].innerHTML which gives '1' which is not type "node" so it will give an error when appending as a child.
remove .innerHTML and it will work
here is an example that removes the first child and append it to the end.
const shuffle = () => {
const parent = document.querySelector("#mainContainer");
const childrens = [...parent.children];
parent.appendChild(childrens.splice(0,1)[0]);
};
<button type="button" onclick=shuffle()> suffel</button>
<div id="mainContainer">
<div class="card">1</div>
<div class="card">2</div>
<div class="card">3</div>
</div>

JavaScript show/hide divs on button click - multiple per page

I am trying to develop a page where there would be multiple divs, each of these divs have a button of which would show a "dropdown" style div below it when clicked.
Currently I have some code which when one button is clicked, it shows all of the "dropdown" styled divs on the page instead of just the one in the same container as the button.
I would like this to be done in pure JavaScript without jquery, any help would be appreciated, thank you!
HTML
<div class="fullResultsContainer">
<div class="resultContainer">
<div class="resultRow">
<!-- This has multiple divs but this is the only one relevant to the issue-->
<div class="resultMenu">
<button class="mobileShowActivityFeedBtn" onclick="mobileActivityLog()"> Show activity feed </button>
</div>
</div>
<div class="mobileDropDown">
<p> This is the content I want to show on button click</p>
</div>
</div>
<div class="resultContainer">
<div class="resultRow">
<!-- This has multiple divs but this is the only one relevant to the issue-->
<div class="resultMenu">
<button class="mobileShowActivityFeedBtn" onclick="mobileActivityLog()"> Show activity feed </button>
</div>
</div>
<div class="mobileDropDown">
<p> This is the content I want to show on button click</p>
</div>
</div>
</div>
JS
function mobileActivityLog() {
var btn = document.getElementsByClassName("mobileShowActivityFeedBtn");
var activity = document.getElementsByClassName("mobileDropDown");
for(var i=0; i<btn.length; i++) {
for(var j=0; i<activity.length; j++) {
if(activity[j].style.display == "none") {
activity[j].style.display = "flex"
} else {
activity[j].style.display = "none"
}
}
}
}

I think the easiest way is to send a parameter to the method and getElementById with a concatenated string with the parameter.
<div class="fullResultsContainer">
<div class="resultContainer">
<div class="resultRow">
<div class="resultMenu">
<button onclick="mobileActivityLog(1)"> Show activity feed </button>
</div>
</div>
<div class="mobileDropDown-1">
<p> This is the content I want to show on button click</p>
</div>
</div>
<div class="resultContainer">
<div class="resultRow">
<div class="resultMenu">
<button onclick="mobileActivityLog(2)"> Show activity feed </button>
</div>
</div>
<div id="mobileDropDown-2">
<p> This is the content I want to show on button click</p>
</div>
</div>
</div>
JS
function mobileActivityLog(index) {
var activity = document.getElementsById("mobileDropDown-" + index);
if(activity.style.display == "none") {
activity.style.display = "flex"
} else {
activity.style.display = "none"
}
}

One of the best possible ways to achieve this is to pass the current context using 'call' in the HTML. Use this context to target the required result container(here 'mobileDropDown' container).
function mobileActivityLog () {
var _this = this;
var activity = _this.closest('.resultContainer').querySelector(".mobileDropDown");
activity.classList.toggle('hide');
}
.hide {
display: none;
}
<div class="fullResultsContainer">
<div class="resultContainer">
<div class="resultRow">
<!-- This has multiple divs but this is the only one relevant to the issue-->
<div class="resultMenu">
<button class="mobileShowActivityFeedBtn" onclick="mobileActivityLog.call(this)"> Show activity feed </button>
</div>
</div>
<div class="mobileDropDown">
<p> This is the content I want to show on button click</p>
</div>
</div>
<div class="resultContainer">
<div class="resultRow">
<!-- This has multiple divs but this is the only one relevant to the issue-->
<div class="resultMenu">
<button class="mobileShowActivityFeedBtn" onclick="mobileActivityLog.call(this)"> Show activity feed </button>
</div>
</div>
<div class="mobileDropDown">
<p> This is the content I want to show on button click</p>
</div>
</div>
</div>

How to change a dynamic button text

Created 3 dynamic divs(sea_p,sea_p_div,div_btns), inside the third(div_btns) created 2 buttons
how can i change the text inside these dynamic buttons before adding to body?
let div = $(`<div class="Search_div"></div>`)
let p = $(`
<div class="sea_p">
<div class="sea_p_div">
<div class="p_img">
<img src="" alt="" width="80" />
<div class="div_span">
<span class="p_name"></span>
<span class="p_surname"></span>
</div>
</div>
<div class="div_btns">
<button class="req_btn req_check1" data-id="">Text1</button>
<button class="req_btn req_check2" data-id="">Text2</button>
</div>
</div>
</div>`)
div.append(p)
//change text here
$('body').append(div)

let div = $(`<div class="Search_div"></div>`)
let p = $(`
<div class="sea_p">
<div class="sea_p_div">
<div class="p_img">
<img src="" alt="" width="80" />
<div class="div_span">
<span class="p_name"></span>
<span class="p_surname"></span>
</div>
</div>
<div class="div_btns">
<button class="req_btn req_check1" data-id="">Text1</button>
<button class="req_btn req_check2" data-id="">Text2</button>
</div>
</div>
</div>`)
div.append(p)
//change text here
p.find(".req_check1").html('New Text');
p.find(".req_check2").html('New Text 2');
$('body').append(div)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

Please try this.
window.onload = function() {
$(".req_check1").html('New Text');
$(".req_check2").html('New Text 2');
}
Thank you.

You can use text() method of jQuery, on the jQuery object of button whose text you want to change.
NOTE : Use it just after appending the p tag to the body.
var buttonWrap = $('.sea_p .div_btns button');
buttonWrap.eq(0).text("Text for button 1");
buttonWrap.eq(1).text("Text for button 2");

How to render an HTMLCollection item?

I have the following html:
<div class="avatars">
<div class="avatar">
<div>
<svg data-jdenticon-value="Oamar Kanji"></svg>
</div>
<h3 class="name">Oamar Kanji</h3>
</div>
<div class="avatar">
<div>
<svg data-jdenticon-value="Oamar Kanji"></svg>
</div>
<h3 class="name">Jane Doe</h3>
</div>
</div>
I am getting a specific element like so and trying to display it inside another element:
<div id="display-here"/>
<script>
let someAvatar = document.getElementsByClassName("avatar").item(0)
document.getElementById('display-here').innerHTML = someAvatar
</script>
This does not work..

You need to use cloneNode
More info here: link
let someAvatar = document.getElementsByClassName("avatar").item(0)
console.log(someAvatar);
var clonedElem = someAvatar.cloneNode(true);
document.getElementById("display-here").appendChild(clonedElem);
<div class="avatars">
<div class="avatar">
<div>
<svg data-jdenticon-value="Oamar Kanji"></svg>
</div>
<h3 class="name">Oamar Kanji</h3>
</div>
<div class="avatar">
<div>
<svg data-jdenticon-value="Oamar Kanji"></svg>
</div>
<h3 class="name">Jane Doe</h3>
</div>
</div>
<div id="display-here">
</div>

Use the following line inside script:
let someAvatar = document.getElementsByClassName("avatar").item(0).innerHTML;
instead of
let someAvatar = document.getElementsByClassName("avatar").item(0)
Now someAvatar will have the HTML content inside of the div. Previously your were having the whole div HTML node.

Accessing multiple elements by getElementsByClassName() with JS

I am trying to create multiple popups on one page that would appear after clicking a button corresponding to them. I currently have them under the same class, as in here:
<div>
<!-- Popup -->
<div class="popup">
<div class="popup-content">
Some text here
</div>
</div>
<!-- Button -->
<img src="button.png" class="popup-button"/>
</div>
The problem is that I am struggling to access individual elements with my javascript code. I am not sure what to replace the manual array accessing ( [0] right now ) with.
<script>
// Get the popup
var popup = document.getElementsByClassName("popup")[0];
// Get the button that opens the popup
var btn = document.getElementsByClassName("popup-button")[0];
// When the user clicks the button, open the popup (hidden by default)
btn.onclick = function() {
popup.style.display = "block";
}
</script>
Now, I could create multiple scripts and access the arrays manually for each element but of course I am trying to automate it, so that script would run depending on which button was clicked. Say, if 5th button was clicked, 5th popup appears. Thank you!

Best way to link multiple elements in Javascript is using an id through the dataset of the elements.
// Get the popup's btn list
var popupsBtn = document.getElementsByClassName("popup-btn");
// Go through the popup's btn list
for (var i = 0; i < popupsBtn.length; i++) {
// Define the onclick event on popup's btn
popupsBtn[i].onclick = function() {
// Get the popup associated to the btn with the data-popup-id
var popup = document.getElementById("popup-" + this.dataset.popupId);
// Use a class to toggle popup visible or not
popup.classList.toggle("visible");
}
}
.popup {
display: none;
}
.popup.visible {
display: block;
}
<!DOCUMENT html>
<html>
<head></head>
<body>
<div>
<div id="popup-1" class="popup">popup 1 here</div>
<img src="button.png" class="popup-btn" data-popup-id="1" />
</div>
<div>
<div id="popup-2" class="popup">popup 2 here</div>
<img src="button.png" class="popup-btn" data-popup-id="2" />
</div>
<div>
<div id="popup-3" class="popup">popup 3 here</div>
<img src="button.png" class="popup-btn" data-popup-id="3" />
</div>
</body>
</html>

Given your HTML, it would probably be easiest to just access the previous sibling of the clicked button to get to the .popup, and then change its style:
document.querySelectorAll('.popup-button').forEach(button => {
button.onclick = () => {
button.previousElementSibling.style.display = 'block';
};
});
.popup {
display: none;
}
<div>
<div class="popup">
<div class="popup-content">
Some text here1
</div>
</div>
<img src="button.png" class="popup-button" />
</div>
<div>
<div class="popup">
<div class="popup-content">
Some text here2
</div>
</div>
<img src="button.png" class="popup-button" />
</div>
<div>
<div class="popup">
<div class="popup-content">
Some text here3
</div>
</div>
<img src="button.png" class="popup-button" />
</div>

You can use other attributes to identify the button. You could not rely on the className alone.
You can use data-id attribute and pass it in the method. using this.

Depending on your HTML structure, there are multiple possibilities.
Anyway, I suggest you to use .querySelectorAll() to get your elements, and then use a .forEach() to execute your code.
I tried to use much of your code to make it work correctly.
With a parent div
// Get all the buttons that opens the popups
var btns = document.querySelectorAll(".popup-button");
btns.forEach(function(btn, index) {
// When the user clicks the button, open the popup that is in the same parent div
btn.onclick = function() {
btn.closest('div').querySelector('.popup').style.display = "block";
}
});
.popup {
display: none;
}
<div>
<div class="popup">
<div class="popup-content">Pop-up 1</div>
</div>
<img src="button.png" class="popup-button" />1
</div>
<div>
<div class="popup">
<div class="popup-content">Pop-up 2</div>
</div>
<img src="button.png" class="popup-button" />2
</div>
<div>
<div class="popup">
<div class="popup-content">Pop-up 3</div>
</div>
<img src="button.png" class="popup-button" />3
</div>
Without a parent div
// Get the popups
var popups = document.querySelectorAll(".popup");
// Get the buttons that opens the popups
var btns = document.querySelectorAll(".popup-button");
btns.forEach(function(btn, index) {
// When the user clicks the button, open the popup (hidden by default)
btn.onclick = function() {
popups[index].style.display = "block";
}
});
.popup {
display: none;
}
<div class="popup">
<div class="popup-content">Pop-up 1</div>
</div>
<img src="button.png" class="popup-button" />
<br>
<br>
<div class="popup">
<div class="popup-content">Pop-up 2</div>
</div>
<img src="button.png" class="popup-button" />
<br>
<br>
<div class="popup">
<div class="popup-content">Pop-up 3</div>
</div>
<img src="button.png" class="popup-button" />
This solution withour parent div will work even if the popups and the buttons are not next to each other. But the order (and index) of the elements need to be the same. See it here:
// Get the popups
var popups = document.querySelectorAll(".popup");
// Get the buttons that opens the popups
var btns = document.querySelectorAll(".popup-button");
btns.forEach(function(btn, index) {
// When the user clicks the button, open the popup (hidden by default)
btn.onclick = function() {
popups[index].style.display = "block";
}
});
.popup {
display: none;
}
<img src="button.png" class="popup-button" />1
<img src="button.png" class="popup-button" />2
<img src="button.png" class="popup-button" />3
<div class="popup">
<div class="popup-content">Pop-up 1</div>
</div>
<div class="popup">
<div class="popup-content">Pop-up 2</div>
</div>
<div class="popup">
<div class="popup-content">Pop-up 3</div>
</div>
Hope it helps.