JavasSript (no jQuery) find multiple classes and add new class to each - javascript

I can find examples using jQuery, but I can't find answers how to do this in pure JavaScript.
Is it possible to combine these two class loops using JavaScript to simplify the code. I am going to end up with approx 20 classes for a project I am working on.
var srtClass1 = document.getElementsByClassName('class1');
for(var i = 0; i < srtClass1.length; i++) {
srtClass1[i].classList.add('newClass');
srtClass1[i].classList.remove('class1');
}
var srtClass2 = document.getElementsByClassName('class2');
for(var i = 0; i < srtClass2.length; i++) {
srtClass2[i].classList.add('newClass');
srtClass2[i].classList.remove('class2');
}

You could try something like this. You just have to fill the array with all of the classes you want to remove.
var classes = ['.class1', '.class2', '.class3'];
var elements = document.querySelectorAll(classes.join(','));
for (let element of elements) {
element.classList.add('newClass');
for (let className in classes) {
element.classList.remove(className);
}
}
.box {
display: block;
width: 100%;
height: 20px;
margin: 0 0 20px 0;
}
.class1 { background: red; }
.class2 { background: green; }
.class3 { background: blue; }
.newClass { background: yellow; }
<div class="box class1"></div>
<div class="box class2"></div>
<div class="box class3"></div>

You can merge the 2 collections:
var srtClass1 = [...document.getElementsByClassName('class1'), ...document.getElementsByClassName('class2')];
for(var i = 0; i < srtClass1.length; i++) {
srtClass1[i].classList.add('newClass');
srtClass1[i].classList.remove('class1');
srtClass1[i].classList.remove('class2');
}
And you can use higher order functions:
[...document.getElementsByClassName('class1'), ...document.getElementsByClassName('class2')].forEach( el => {
el.classList.add('newClass');
el.classList.remove('class1');
el.classList.remove('class2');
});
And even better (since classList.remove supports multiple arguments):
[...document.getElementsByClassName('class1'), ...document.getElementsByClassName('class2')].forEach( el => {
el.classList.add('newClass');
el.classList.remove('class1', 'class2');
});
Or if you want you can use querySelectorAll:
document.querySelectorAll('.class1, .class2').forEach(el => {
el.classList.add('newClass');
el.classList.remove('class1', 'class2');
});

Perhaps try making a list of the classes, then iterating over that instead:
function changeClasses() {
let classNames = ['class1', 'class2'];
classNames.forEach(className => {
const node = document.querySelector(`.${className}`);
if (node != null) {
node.classList.add('newClass');
node.classList.remove(className);
}
});
}
.class1 {
color: green;
}
.class2 {
color: blue;
}
.newClass {
color: red;
}
<body>
<div class="class1">class1</div>
<div class="class2">class2</div>
<button onclick="changeClasses()">Change classes</button>
</body>

Related

How to inject an id attribute to HTML with its value coming from a for loop using JavaScript?

const renderProgress = () => {
let qIndex = 0;
const lastQuestion = 20
const queryAllProgress = document.getElementsByClassName("query__all-progress");
const queryAllProgressId = document.createAttribute("id");
for (qIndex; qIndex <= lastQuestion; qIndex++) {
queryAllProgressId.value += qIndex;
queryAllProgress.setAttributeNode(queryAllProgressId);
}
};
.query__all-progress {
width: 0.9rem;
height: 0.9rem;
margin: 0 0.03rem;
border: 1px solid grey;
display: inline-block;
border-radius: 40%;
}
<div class="query__all-progress"></div>
As you can see, I am trying to get the div element by the class name query__all-progress 'cause I need to give it an attribute of id="". And, the value of the id should be from the for loop, which is the qIndex. I tried to do this but it doesn't work. Please help.
I'm just trying to refactor this code guys. Please help:
const renderProgress = () => {
const lastQuestion = 20;
let qIndex = 0;
const queryProgress = document.getElementById("query__progress");
for (qIndex; qIndex <= lastQuestion; qIndex++) {
queryProgress.innerHTML += `<div class='query__all-progress' id="${qIndex}"></div>`;
}
};
You can try to solve it like this:
In your .html file create a element to serve as a container
<div id="container"></div>
I modified your function a bit like this:
const renderProgress = () => {
// COUNTING VARIABLES
let qIndex = 0;
const lastQuestion = 20
// TO STORE EACH ELEMENT
let querys = '';
// PROCESS
for (qIndex; qIndex <= lastQuestion; qIndex++) {
querys += '<div class="query__all-progress" id="'+ qIndex +'"></div>';
}
// INJECTING GENERATED ELEMENTS TO CONTAINER
document.getElementById('container').insertAdjacentHTML('afterbegin', querys);
}
renderProgress();
.css stays the same
.query__all-progress {
width: 0.9rem;
height: 0.9rem;
margin: 0 0.03rem;
border: 1px solid grey;
display: inline-block;
border-radius: 40%;
}
You should have something like this:
And in the inspector:
I hope it helps you.

How to add hover effect upon mouseover to all divs on a page?

I have a 16x16 grid of small squares. I have added a permanent "hover" effect to make the very first box turn red when I put my mouse over it. However, I want to add the same effect to all of the boxes on the page. I can't figure out how to do it - I have tried to add an event listener to the whole page and used target.nodeName and target.NodeValue, but to no avail. I have included the working version where the fix box turns red on mouseover.
var n=16; //take grid column value as you want
const bigContainer = document.querySelector('.bigContainer')
for(var i = 1; i < n; i++) {
bigContainer.innerHTML+='<div class="row">';
for(j = 0; j < n; j++) {
bigContainer.innerHTML+='<div class="smallBox">';
}
}
const smallBox = document.querySelector('.smallBox');
smallBox.addEventListener('mouseover', () => {
smallBox.classList.add('permahover');
});
.smallBox {
border: 1px solid black;
width: 20px;
height: 20px;
display: inline-block;
}
.permahover {
background: red;
}
h1 {
text-align: center;
}
.bigContainer {
text-align: center;
}
<h1>Etch-a-Sketch Assignment - The Odin Project</h1>
<div class="bigContainer">
</div>
The immediate problem you are having is that this is only querying, and subsequently adding an event listener to, one element.
const smallBox = document.querySelector('.smallBox');
smallBox.addEventListener('mouseover', () => {
smallBox.classList.add('permahover');
});
In the above portion of your code, querySelector only returns the first matching element. You may be looking for querySelectorAll here which returns a NodeList of matching elements.
You have two options (perhaps others if you want to restructure your code further). The naive approach is to, in fact, query for all of the cells and add event listeners to each of them.
var n=16; //take grid column value as you want
const bigContainer = document.querySelector('.bigContainer')
for(var i = 1; i < n; i++) {
bigContainer.innerHTML+='<div class="row">';
for(j = 0; j < n; j++) {
bigContainer.innerHTML+='<div class="smallBox">';
}
}
const smallBoxes = document.querySelectorAll('.smallBox');
[...smallBoxes].forEach(smallBox => {
smallBox.addEventListener('mouseover', () => {
smallBox.classList.add('permahover');
});
})
.smallBox {
border: 1px solid black;
width: 20px;
height: 20px;
display: inline-block;
}
.permahover {
background: red;
}
h1 {
text-align: center;
}
.bigContainer {
text-align: center;
}
<h1>Etch-a-Sketch Assignment - The Odin Project</h1>
<div class="bigContainer">
</div>
Another option is to use event delegation as you identified. Here is how you can leverage that. Note: this approach is a bit tricker for an aggressive event like "mouseover" as you may get false positive targets (like the outer container for example).
var n=16; //take grid column value as you want
const bigContainer = document.querySelector('.bigContainer')
for(var i = 1; i < n; i++) {
bigContainer.innerHTML+='<div class="row">';
for(j = 0; j < n; j++) {
bigContainer.innerHTML+='<div class="smallBox">';
}
}
bigContainer.addEventListener('mouseover', e => {
var target = e.target
if (target !== bigContainer) {
target.classList.add('permahover')
}
})
.smallBox {
border: 1px solid black;
width: 20px;
height: 20px;
display: inline-block;
}
.permahover {
background: red;
}
h1 {
text-align: center;
}
.bigContainer {
text-align: center;
}
<h1>Etch-a-Sketch Assignment - The Odin Project</h1>
<div class="bigContainer">
</div>
You need to use a delegation event, because all the small boxes don't exist on the page when the page is loaded (You can figure out in the inspector element that only your first box has the event listener).
So you listen the whole container (because it is always on the page on load)
bigContainer.addEventListener('mouseover', () => {
// Code for checking if we hovered a small div & if yes applying the style
});
...and then do a comparaison with the event.target (which will be the small div hovered)
if (event.target.matches('.smallBox')) {
event.target.classList.add('permahover');
}
var n=16; //take grid column value as you want
const bigContainer = document.querySelector('.bigContainer')
for(var i = 1; i < n; i++) {
bigContainer.innerHTML+='<div class="row">';
for(j = 0; j < n; j++) {
bigContainer.innerHTML+='<div class="smallBox">';
}
}
const smallBox = document.querySelector('.smallBox');
bigContainer.addEventListener('mouseover', () => {
if (event.target.matches('.smallBox')) {
event.target.classList.add('permahover');
}
});
.smallBox {
border: 1px solid black;
width: 20px;
height: 20px;
display: inline-block;
}
.permahover {
background: red;
}
h1 {
text-align: center;
}
.bigContainer {
text-align: center;
}
<h1>Etch-a-Sketch Assignment - The Odin Project</h1>
<div class="bigContainer">
</div>
You can use forEach method to loop through all boxes and add eventListener on each one.
If all of them have .smallBox class you can do it like this:
const smallBoxes = document.querySelectorAll('.smallBox');
smallBoxes.forEach(box => box.addEventListener('mouseover', () => {
smallBox.classList.add('permahover');
}))
I hope it helped you!
let smallBoxes = document.querySelectorAll('.smallBox');
[...smallBoxes].forEach(el => {
el.addEventListener('mouseover', e => e.target.classList.add('permahover'));
});
you should set the eventlistener to your DOM and ask if the trigger element are one of your elements which are that specific class. So you can handle every element with that class.
var n = 16; //take grid column value as you want
const bigContainer = document.querySelector('.bigContainer')
for (var i = 1; i < n; i++) {
bigContainer.innerHTML += '<div class="row">';
for (j = 0; j < n; j++) {
bigContainer.innerHTML += '<div class="smallBox">';
}
}
document.addEventListener('mouseover', function(e) {
if (e.target && e.target.className == 'smallBox') {
var target = e.target;
target.classList.add('permahover');
}
});
Working js fiddle: https://jsfiddle.net/nwukf205/
hope i could help you :)
if you got questions just ask
Have you tried the :hover selector? Not sure if you want specify any dynamic actions here, but it's easy to do basic stuff.
https://www.w3schools.com/cssref/sel_hover.asp
a:hover {
background-color: yellow;
}
I haven't tried your example myself but something similar to this has been answered here:
Hover on element and highlight all elements with the same class

javascript div background color with important

Hi i been trying to change some divs style with javascript and it changes the style but if the divs display is changed to none and back to block it resets the style? i tried to fix this with important but that didn't seem to work? any ideas why this happens or if there is a better way i could achieve what i'm trying to do?
var Style = document.querySelectorAll('#mainui-features, #mainui-modes, #mainui-offers, #mainui-party, #mainui-play, #mainui-user, #mainui-settings');
for (var i = 0; i < Style.length; i++) {
Style[i].style.borderRadius = '1em'; // standard
Style[i].style.MozBorderRadius = '1em'; // Mozilla
Style[i].style.WebkitBorderRadius = '1em'; // WebKitww
Style[i].style.color = "#D35400";
Style[i].style.border = "2px solid #D35400";
Style[i].style.setProperty("background-image", "linear-gradient(to right, #92FE9D, #00C9FF)", "important");
}
Instead of inline styles you can a class
var Style = document.querySelectorAll('#mainui-features, #mainui-modes, #mainui-offers, #mainui-party, #mainui-play, #mainui-user, #mainui-settings');
for (var i = 0; i < Style.length; i++) {
Style[i].classList.add('styles')
}
function hide() {
for (var i = 0; i < Style.length; i++) {
Style[i].classList.add('hide')
}
}
function show() {
for (var i = 0; i < Style.length; i++) {
Style[i].classList.remove('hide')
}
}
.styles {
border-radius: 1em;
-moz-border-radius: 1em;
color: #D35400;
border: 2px solid #D35400;
background-image: linear-gradient(to right, #92FE9D, #00C9FF)
}
.hide {
display: none
}
<div id="mainui-features">1</div>
<div id="mainui-modes">2</div>
<div id="mainui-offers">3</div>
<div id="mainui-party">4</div>
<button onclick="hide()">Hide</button>
<button onclick="show()">Show</button>
Not sure what you're doing wrong, but the way you describe your requirements works without any problem. Maybe this helps in some way.
I didn't include all the IDs.
// Store all elements in an array
const elements = [...document.querySelectorAll("#mainui-features, #mainui-modes, #mainui-offers, #mainui-party")];
// Assign CSS values to each element in the array
elements.map( el => {
el.style.borderRadius = "1em";
el.style.color = "#D35400";
el.style.border = "2px solid #D35400";
el.style.backgroundImage = "linear-gradient(to right, #92FE9D, #00C9FF)";
});
// Assign display:none to each element
elements.map( el => el.style.display = "none" );
// And make them display:block again
elements.map( el => el.style.display = "block" );
div {
height: 1rem;
width: 3rem;
}
<div id="mainui-features">1</div>
<div id="mainui-modes">2</div>
<div id="mainui-offers">3</div>
<div id="mainui-party">4</div>

Passing around event object without jquery

Apologies for the basic question. It's hard to find information about JS event handling without finding an explanation that includes jQuery, and I'm trying to manipulate the DOM with pure Javascript. It's been helping me better understand how the browser works.
I'm trying to call a function to add an additional class to elements with the same class.
Can someone explain the correct syntax here?
Is it necessary to reference the ID?
I've tried a number of approaches. Thanks so much.
function animateSquare(e) {
var id = e.target.id
var el = document.getElementById(id);
el.className = el.className + "newClass";
};
window.onload = function() {
var anim = document.getElementsByClassName("squareThing");
for (var i = 0; i < anim.length; i++) {
anim[i].click(function(e) {
animateSquare(e);
});
}
}
<div class="squarething" id="one"></div>
<div class="squarething" id="two"></div>
The standard Javascript method to add event bindings, analogous to .on() in jQuery, is addEventListener.
And when you add a class to el.className, you need to include a space before it, to separate it from the existing classes.
You don't need to use getElementById(id), since e.target is the element itself -- you're getting the element, getting its ID, and then looking up the element again by ID, which is redundant.
function animateSquare(e) {
var el = e.target;
el.className = el.className + " newClass";
};
window.onload = function() {
var anim = document.getElementsByClassName("squarething");
for (var i = 0; i < anim.length; i++) {
anim[i].addEventListener('click', function(e) {
animateSquare(e);
});
}
}
.squarething {
width: 50px;
height: 50px;
background-color: green;
margin: 2px;
}
.newClass {
background-color: red;
}
<div class="squarething" id="one"></div>
<div class="squarething" id="two"></div>
This should be enough. Try it:
function animateSquare() {
this.className += " newClass";
}
window.onload = function() {
var anim = document.getElementsByClassName("squarething");
for (var i = 0; i < anim.length; i++) {
anim[i].onclick = animateSquare;
}
}
.squarething {
padding: 1em;
margin: .5em;
float: left;
background: blue;
}
.squarething.newClass {
background: orange;
}
<div class="squarething" id="one"></div>
<div class="squarething" id="two"></div>
.click(handler) is a jQuery method - you want the .onclick or addEventListener methods:
window.onload = function() {
var anim = document.getElementsByClassName("squarething");
for (var i = 0; i < anim.length; i++) {
anim[i].onclick = animateSquare;
}
}
You can also use this inside your handler function:
function animateSquare(e) {
this.className = el.className + "newClass";
};

How to add multiple divs with appendChild?

I am trying to make a chessboard using javascript and creating 64 divs with it.
The problem is, that it creates only the first div.
Here is the code:
div {
width: 50px;
height: 50px;
display: block;
position: relative;
float: left;
}
<script type="text/javascript">
window.onload=function()
{
var i=0;
var j=0;
var d=document.createElement("div");
for (i=1; i<=8; i++)
{
for (j=1; j<=8; j++)
{
if ((i%2!=0 && j%2==0)||(i%2==0 && j%2!=0))
{
document.body.appendChild(d);
d.className="black";
}
else
{
document.body.appendChild(d);
d.className="white";
}
}
}
}
</script>
As t-j-crowder has noted, the OP's code only creates one div. But, for googlers, there is one way to append multiple elements with a single appendChild in the DOM: by creating a documentFragment.
function createDiv(text) {
var div = document.createElement("div");
div.appendChild(document.createTextNode(text));
return div;
}
var divs = [
createDiv("foo"),
createDiv("bar"),
createDiv("baz")
];
var docFrag = document.createDocumentFragment();
for(var i = 0; i < divs.length; i++) {
docFrag.appendChild(divs[i]); // Note that this does NOT go to the DOM
}
document.body.appendChild(docFrag); // Appends all divs at once
The problem is, that it creates only the first div.
Right, because you've only created one div. If you want to create more than one, you must call createElement more than once. Move your
d=document.createElement("div");
line into the j loop.
If you call appendChild passing in an element that's already in the DOM, it's moved, not copied.
window.onload=function()
{
var i=0;
var j=0;
for (i=1; i<=8; i++)
{
for (j=1; j<=8; j++)
{
if ((i%2!=0 && j%2==0)||(i%2==0 && j%2!=0))
{
var d=document.createElement("div");
document.body.appendChild(d);
d.className="black";
}
else
{
var d=document.createElement("div");
document.body.appendChild(d);
d.className="white";
}
}
}
}
Although what T.J. Crowder writes works fine, I would recommend rewriting it to the code below, using a documentFragment, like Renato Zannon suggested. That way you will only write to the DOM once.
window.onload = function() {
var count = 5,
div,
board = document.getElementById('board'),
fragment = document.createDocumentFragment();
// rows
for (var i = 0; i < count; ++i) {
// columns
for (var j = 0; j < count; ++j) {
div = document.createElement('div');
div.className = (i % 2 != 0 && j % 2 == 0) || (i % 2 == 0 && j % 2 != 0) ? 'black' : 'white';
fragment.appendChild(div);
}
}
board.appendChild(fragment);
};
#board {
background-color: #ccc;
height: 510px;
padding: 1px;
width: 510px;
}
.black,
.white {
float: left;
height: 100px;
margin: 1px;
width: 100px;
}
.black {
background-color: #333;
}
.white {
background-color: #efefef;
}
<div id="board"></div>
function crt_dv(){
dv=document.createElement('div'),document.body.appendChild(dv)
};
crt_dv(),dv.className='white';crt_dv(),dv.className='black';
Also use: for(i=0;i<2;i++)

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