Develop Reference

change properties of two divs with one onclick and querySelectorAll()

I have multiple elements that are seperatet in two divs. The first div contains a Text and the second div a color.
When I click on one element the text and color should change and if I click it again it should change back.
The problem is that no matter which one I click, its always the last one which changes.
The HTML part:
<style>
.colorGreen {
background-color: green;
}
.colorRed {
background-color: red;
}
</style>
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
The JavaScript part:
<script type='text/javascript'>
var box1Temp = document.querySelectorAll(".box1");
var box2Temp = document.querySelectorAll(".box2");
for (var i = 0; i < box1Temp.length; i++) {
var box1 = box1Temp[i];
var box2 = box2Temp[i];
box2.onclick = box1.onclick = function() {
if (box1.classList.contains("colorGreen")) {
box1.classList.add("colorRed");
box1.classList.remove("colorGreen");
box2.innerHTML = "Text2";
} else {
box1.classList.add("colorGreen");
box1.classList.remove("colorRed");
box2.innerHTML = "Text1";
}
}
}
</script>
It works, when I use only one div.
Then I can use 'this', instead of the 'box1' variable, to addres the right element.
But if I replace 'box1' with 'this' its still the text div that changes.
(I know it's obvious that this is happening, but I'm lost)

With a few small tweaks, this can be written a lot more cleanly:
// Capture click event for parent container, .toggle-set
for (const ele of document.querySelectorAll(".toggle-set")) {
ele.addEventListener("click", function() {
// Grab text and color elements
const textToggle = ele.querySelector(".toggle-text");
const colorToggle = ele.querySelector(".toggle-color");
// Toggle text
// NOTE: This could use further refinement with regex or something similar to strip whitespace before comparison
textToggle.textContent = textToggle.textContent == "Text1" ? "Text2" : "Text1";
// Toggle css classes
colorToggle.classList.toggle("colorGreen");
colorToggle.classList.toggle("colorRed");
});
}
.colorGreen { background-color: green; }
.colorRed { background-color: red; }
<div class="toggle-set">
<div class="toggle-text">Text1</div>
<div class="toggle-color colorGreen">
O
</div>
</div>
<div class="toggle-set">
<div class="toggle-text">Text1</div>
<div class="toggle-color colorGreen">
O
</div>
</div>

Your code is so confused
You were right for the this option.
you can do with simple onclick function :
function change(el){
box1 = el.querySelector('.box1');
box2 = el.querySelector('.box2');
if (box1.classList.contains("colorGreen")) {
box1.classList.add("colorRed");
box1.classList.remove("colorGreen");
box2.innerHTML = "Text2";
} else {
box1.classList.add("colorGreen");
box1.classList.remove("colorRed");
box2.innerHTML = "Text1";
}
}
<style>
.colorGreen {
background-color: green;
}
.colorRed {
background-color: red;
}
</style>
<div onclick="change(this)">
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
</div>
<div onclick="change(this)">
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
</div>
<div onclick="change(this)">
<div class="box2">Text1</div>
<div class="box1 colorGreen">O</div>
</div>

I think following code snippet would help you to get your desired result
let box1 = document.querySelectorAll(".box1");
let box2 = document.querySelectorAll(".box2");
box1.forEach((b1,i) => {
b1.addEventListener("click",(ev) => {
ev.target.classList.toggle("colorGreen");
ev.target.classList.toggle("colorRed");
console.log(box2[i]);
if(ev.target.classList.contains("colorGreen")){
box2[i].textContent = "Text1";
}else{
box2[i].textContent = "Text2"
}
})
})

Shifting forward in an array when iterating over elements

I have repeating elements (section) on a page. I want to iterate the background colors of the elements between three colors that are held in a array. And within some of those elements I have text (p) that I want to iterate through those same colors, except I want it to be the next color in the array as the background.
So if I have an array that looks like ["111111", "222222", "333333"], I want the background color of the first section to be #111111 and the color of the first p to be #222222. Also there are more elements on the page than there are items in the array so we need to loop back through the array. The page when complete should look like:
<body>
<section style="background-color: #111111;">
<p style="color: #222222;">foo bar</p>
</section>
<section" style="background-color: #222222;">
<p style="color: #333333;">foo bar</p>
</section>
<section style="background-color: #333333;">
<!--no p in this one-->
</section>
<section style="background-color: #111111;">
<p style="color: #222222;">foo bar</p>
</section>
</body>
I have the background-color part done but I can't figure out how to shift to the next item in the array and start over at the first item when necessary.
var bgColors = ["111111", "222222", "333333"];
$('section').each(function(i) {
var bgColor = bgColors[i % bgColors.length];
$(this).css('background-color', '#'+bgColor);
// How to do text color???
$(this).find("p").css('color', ???);
});
The script should be flexible so you can add and change colors. Thanks.
EDIT: I realized I left out an important point which is that not every section has a p so you can't just iterate through them each independently. Also due to a c&p mishap my html didn't match my JS. Apologies.

Just use i+1 for the modulo for the foreground
It is the same logic you already apply for the bgColor, you just need to go one more for the foreground
var bgColors = ["red", "green", "blue", "yellow"];
$(function() {
$('.section').each(function(i) {
var bgColor = bgColors[i % bgColors.length];
var fgColor = bgColors[(i + 1) % bgColors.length];
$(this).css('background-color', bgColor);
$(this).find(".text").css('color', fgColor);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>

You can have a logic like
var bgColorIndex = i % bgColors.length;
var bgColor = bgColors[i % bgColors.length];
$(this).css('background-color', '#'+bgColor);
var fgColor = bgColorIndex + 1 === bgColors.length ? bgColors[0] : bgColors[bgColorIndex + 1];
$(this).find("p").css('color', fgColor);
It checks if the next index is equal to the length, set the color to the first item, otherwise set to the next color by incrementing.
Code example
var bgColors = ['red', 'blue', 'green', 'yellow'];
$(document).ready(function() {
$('.section').each(function(i) {
var bgColorIndex = i % bgColors.length;
var bgColor = bgColors[i % bgColors.length];
$(this).css('background-color', bgColor);
var fgColor = bgColorIndex + 1 === bgColors.length ? bgColors[0] : bgColors[bgColorIndex + 1];
$(this).find(".text").css('color', fgColor);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<body>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>
<div class="section">
<div class="text">foo bar</div>
</div>
</body>

Do you specifically need to do this in JavaScript for some reason, or would a pure CSS solution be preferable? Because you can achieve the same effect with :nth-child():
.section:nth-child(3n+1) {
background-color: #111;
}
.section:nth-child(3n+1) .text {
color: #222;
}
.section:nth-child(3n+2) {
background-color: #222;
}
.section:nth-child(3n+2) .text {
color: #333;
}
.section:nth-child(3n+3) {
background-color: #333;
}
.section:nth-child(3n+3) .text {
color: #111;
}
More performant, no FOUC, works for people with JavaScript disabled, etc.
Codepen: https://codepen.io/anon/pen/aLyOwJ

get element by id - using variable

I'm trying to use the function getElementById().
I have several ID's that i want to change style of, one by one, in an increasing order. I have a variable called numberOfTimes, which increases with 1 every time.
The names of the ID's are 1, 2, 3, 4 etc, and up to 8.
Is there some way I can use the variable-name in the function - if not, how should you solve this?
var numberOfTimes = 1;
document.getElementById(1).style.backgroundColor = "green";

Let's pretend your IDs look like this idx (x stands for the number). You can do:
var numberOfTimes = 8;
for (var i = 1; i <= numberOfTimes; ++i) {
document.getElementById('id' + i).style.backgroundColor = "green";
}

Solution if you really specific to change the color of the element one by one. Then you can use for loop.
second
document.getElementById(1)
You can use integer value directly but preferable you should use id with some text.
just use like this in for loop
for(var i=1;i<=8;i++){
document.getElementById("div_"+i).style.backgroundColor = "green";
}

As stated in other answers and comments, it is highly recommended not to use numbers only as IDs, also you can pick these divs upon a unique class name which will get you an array of them, and just loop through the array just like in this fiddle.
However here's the code JS Fiddle
var id = 1;
changeBG();
function changeBG() {
document.getElementById('el-' + id).style.backgroundColor = "green";
id++;
var t = setTimeout(changeBG, 500);
}
div {
width: 100%;
height: 50px;
margin-bottom: 5px;
display: inline-block;
}
<div id="el-1"></div>
<div id="el-2"></div>
<div id="el-3"></div>
<div id="el-4"></div>
<div id="el-5"></div>
<div id="el-6"></div>
<div id="el-7"></div>
<div id="el-8"></div>

Numbers-only ID are not a good practice, I hope this quetion is in the purpose of learning.
for(var i = 1; i < 9; i++){
document.getElementById(i).style['background'] = 'green';
}
div {
width:100%;
height:20px;
margin-bottom:10px;
}
<div id="1"></div>
<div id="2"></div>
<div id="3"></div>
<div id="4"></div>
<div id="5"></div>
<div id="6"></div>
<div id="7"></div>
<div id="8"></div>

Javascript loop for every 2 classes

Hi I've got a small issue but not sure how to solve it by javascript/jquery. Essentially ive got several div classes but what i want to do is to create a loop to add a class on certain divs, without having to add an id on them manually but to add a id or class through the javascript code.
Heres an idea of what i mean:
<div></div><div></div>
<div></div><div></div>
<div></div><div></div>
<div></div><div></div>
This is what i currently have so lets say two divs will be a row. I want it so a a class is added in a certain way to make it like this:
<div class="green"></div> <div></div>
<div></div> <div class="green"></div>
<div class="green"></div> <div></div>
<div></div> <div class="green"></div>
So i am guessing it will be some sort of loop for every 2 divs then it will repeat in reverse.

using jquery
Use this loop to add class after 2 div
DEMO
$('div').each(function(i){
if((i%3) === 0){
$(this).addClass('green')
}
});
using :odd and :even selector
DEMO
$( "div:odd" ).addClass( "green" );
for even
$( "div:even" ).addClass( "green" );

Basically you want Zig-Zag.
There is no need of loops. You can use :nth-child selector as follow:
$('div:nth-child(4n+1)').addClass('green'); // Selects 1, 5, 9, 13, ...
$('div:nth-child(4n)').addClass('green'); // Selects 4, 8, 12, 16, ...
Demo
Here is the pure CSS Demo.
body {
width: 120px;
}
div {
height: 50px;
width: 50px;
background: red;
margin: 5px;
float: left;
}
div:nth-child(4n+1) {
background: green;
}
div:nth-child(4n) {
background: green;
}
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>

HTML:
<div class="wrapper">
<div class="element">1</div>
<div class="element">2</div>
<div class="element">3</div>
<div class="element">4</div>
<div class="element">5</div>
<div class="element">6</div>
</div>
Pure Javascript:
var parents = document.getElementsByClassName("wrapper");
for (var i = 0, ii = parents.length; i < ii; i++) {
var parent = parents[i],
children = parent.children;
for (var j = 0, jj = children.length; j < jj; j++) {
var elem = children[j];
if (j % 2 === 0) {
elem.classList.add("highlight");
}
}
}
Demo
OR
jQuery:
$(".element:odd").addClass("highlight");
Demo

If just for show different background, you may use css nth-child(even) or nth-child(odd), as should sample in the table:
tr:nth-child(even) {background: #CCC}
tr:nth-child(odd) {background: #FFF}

You can grab your divs with a for loop using childNodes () javascript function. If the index is odd then you can apply manually your class.
something like this:
var nodes = parentElement.childNodes();
for (var i = 0; i < nodes.length; i++) {
if (i % 2 == 0) continue;
nodes[i].className = "green";
}

Change child element of array item (syntax)

I have a few divs which are using the same class.
Inside the divs are three more divs with identical classes.
<div class="plane">
<div class="win1">Lorem ipsum</div>
<div class="win2">Dolor sit</div>
<div class="win3">amet.</div>
</div>
<div class="plane">
<div class="win1">Lorem ipsum</div>
<div class="win2">Dolor sit</div>
<div class="win3">amet.</div>
</div>
var allPlanes = $('.plane');
for (var i = 0; i < allPlanes.length; i++) {
var onePlane = allPlanes[i];
var baseHeight = 10;
$(onePlane + " .win1").css("height", parseInt(baseHeight*1));
$(onePlane + " .win2").css("height", parseInt(baseHeight*2));
$(onePlane + " .win3").css("height", parseInt(baseHeight*3));
}
(Don't mind about the names. It's just an example...)
Now I made an array with the outside divs and I can select the single divs inside. But I did not get the right syntax for the child divs inside.
Can anyone help?
My Fiddle: http://jsfiddle.net/SchweizerSchoggi/559xvww6/

Change you script to this:
var allPlanes = $('.plane');
var baseHeight = 10;
$(".plane > .win1").css("height", parseInt(baseHeight*1)+"px");
$(".plane > .win2").css("height", parseInt(baseHeight*2)+"px");
$(".plane > .win3").css("height", parseInt(baseHeight*3)+"px");
You don't need the for loop in such a case.
A prettier way:
var baseHeight = 10;
for (var i = 1; i <= 3; i++) {
$(".plane > .win"+i).css("height", parseInt(baseHeight*i)+"px");
}
http://jsfiddle.net/559xvww6/3/
If you don't want to use a for loop and want to dinamically configure from an array:
var baseHeight = 10;
$.map([1,2,3], function(i) {
$(".plane > .win"+i).css("height", parseInt(baseHeight*i)+"px");
});
http://jsfiddle.net/559xvww6/10/
Edit:: Just a side note: all these approachs are valid, but that doesn't mean that they are the best / most efficient ones. Feel free to use the one you like the most, understand it and try to use it or adapt it to your very personal situation. The "easiest" approach is surely the first one, but it is also the longest one.

isn't this one is better:
var base = 10;
$('.plane > div').css('height', function(){
return base*($(this).index()+1)
});
.plane {
background-color: #ccc;
border: solid 1px #cdcdcd;
margin-bottom: 15px;
}
.plane > .win1 { background-color: #ddd; }
.plane > .win2 { background-color: #eee; }
.plane > .win3 { background-color: #fff; }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="plane">
<div class="win1">Lorem ipsum</div>
<div class="win2">Dolor sit</div>
<div class="win3">amet.</div>
</div>
<div class="plane">
<div class="win1">Lorem ipsum</div>
<div class="win2">Dolor sit</div>
<div class="win3">amet.</div>
</div>

You cannot use + operator between a jQuery object and a string.
The correct way to do it is this:
$(".win1", onePlane).css("height", parseInt(baseHeight*1));
$(".win2", onePlane).css("height", parseInt(baseHeight*2));
$(".win3", onePlane).css("height", parseInt(baseHeight*3));
Each of these queries translates to: select all elements with .winX that are inside the jQuery object onePlane.

I would use all the same class names inside the nest and then just do $('.plane:eq(0) .win:eq(2)').html()
alert( $('.plane:eq(0) .win:eq(2)').html() );
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="plane">
<div class="win">Lorem ipsum</div>
<div class="win">Dolor sit</div>
<div class="win">amet.</div>
</div>
<div class="plane">
<div class="win">Lorem ipsum</div>
<div class="win">Dolor sit</div>
<div class="win">amet.</div>
</div>

if your classes are fixed then you can do with this code
$(".win1", $(".plane")).css("height", parseInt(baseHeight*1));
$(" .win2", $(".plane")).css("height", parseInt(baseHeight*2));
$(" .win3", $(".plane")).css("height", parseInt(baseHeight*3));

You can do using each loop of plane class.
$('.plane').each(function(){
baseHeight = 10;
$(this).find(".win1").css("height", parseInt(baseHeight*1));
$(this).find(".win2").css("height", parseInt(baseHeight*2));
$(this).find(".win3").css("height", parseInt(baseHeight*3));
});
Demo