Develop Reference

Uneven CSS Column Grids

From my research in this problem, I've learned CSS grids appear to capable of quite complex behaviour. My scenario is simpler and I was expecting to have 4 evenly spaced panel boxes with code below. My question is why the horizontal gap is not centred in the middle vertically? I worked through trail&error to test various combinations of alignment, justification and grid specs but could not find a solution. What do I need to add to my code to have the gap centred vertically on the page?
.main-container {
display: grid;
grid-template-columns: repeat(2, 1fr);
grid-gap: 20px;
height: 100vh;
align-items: stretch;
margin: 0;
padding: 0;
justify-content: space-between;
}
.container {
border: 3px solid black;
display: flex;
position: relative;
flex-direction: column;
margin: 0;
padding: 0;
}
.shared {
justify-content: center;
border: none;
}
.sub-container {
border: 3px solid black;
align-items: stretch;
height: 100%;
margin: 0;
padding: 0;
}
<div class="main-container">
<div class="container" id="A">
<h1>Section A</h1>
<p id="A-values">A Values</p>
</div>
<div class="container" id="B">
<h1>Section B</h1>
<p id="B-values">B Values</p>
</div>
<div class="container" id="C">
<h1>Section C</h1>
<p id="C-values">C Values</p>
</div>
<div class="container shared" id="D">
<div class="sub-container">
<h2>SubSection D1</h2>
<p id="D1-values">D1 Values</p>
</div>
<div class="sub-container">
<h2>SubSection D2</h2>
<p id="D2-values">D2 Values</p>
</div>
<div class="sub-container">
<h2>SubSection D3</h2>
<p id="D3-values">D3 Values</p>
</div>
</div>
</div>

By default, the height is set to match the longest item on a row, the height on the bottom row is different to the top simply because there's more content in one of it's columns.
Try setting the rows as you have the columns, add grid-template-rows: repeat(2, 1fr); to the main-container class

How to Let Float Items Split the Blank Area in Average?

Please run this demo:
.app {
background:pink;
width: 90vw;
overflow: hidden;
}
.app__item {
background: lightblue;
width: 200px;
float :left;
margin:5px;
height: 40px;
}
.app__item:last-child {
float: right;
}
.app__item--size2 {
height: 90px;
}
<div class="app">
<div class="app__item app__item--size2">1</div>
<div class="app__item">2</div>
<div class="app__item">3</div>
<div class="app__item">4</div>
<div class="app__item">5</div>
<div class="app__item">6</div>
<div class="app__item">7</div>
<div class="app__item">8</div>
<div class="app__item">9</div>
<div class="app__item">10</div>
<div class="app__item">
<button>search</button>
</div>
</div>
Please notice the red color text which is what I want:
How to Let Float Items Split the Blank Area in Average?
This gif point out what I want and also the reason why I am using float layout.
If using flex, the result would be
.app {
background:pink;
width: 80vw;
display: flex;
flex-flow: row wrap;
}
.app__item,
.app__item_wrapper {
margin:5px;
width: 200px;
flex: 0 0 auto;
}
.app__item {
background: lightblue;
height: 40px;
}
.app__item_wrapper {
display: flex;
flex-flow: column;
justify-content: space-between;
}
.app__item--size2 {
height: 90px;
}
.app__item--inner {
margin:0;
flex: 0 0 auto;
}
<div class="app">
<div class="app__item app__item--size2">1</div>
<div class=" app__item_wrapper app__item--size2">
<div class="app__item app__item--inner">2</div>
<div class="app__item app__item--inner">3</div>
</div>
<div class=" app__item_wrapper app__item--size2">
<div class="app__item app__item--inner">4</div>
<div class="app__item app__item--inner">5</div>
</div>
<div class="app__item">6</div>
<div class="app__item">7</div>
<div class="app__item">8</div>
<div class="app__item">
<button>search</button>
</div>
</div>
And the con is that it won't work well when viewport is changing. See this:
and this is the con:

If I understand correctly, you're wanting the cells to the right of "cell 1" to stretch-to-fill the reaming horizontal space of the enclosing div (with pink background).
You could use CSS Grid to achieve this as shown below:
.app {
background:pink;
width: 90vw;
padding:5px;
display:grid;
/* Cause first column with to be 200px, remaining two columns
to scale to fit remaining width */
grid-template-columns: 200px repeat(2, 1fr);
/* Set spacing between cells */
grid-gap:10px;
}
.app__item {
background: lightblue;
width: 100%;
height: 40px;
}
.app__item--size2 {
/* Cause top left cell to occupy two rows */
grid-row: 1 / 3;
height:100%;
}
<div class="app">
<div class="app__item app__item--size2">1</div>
<div class="app__item">2</div>
<div class="app__item">3</div>
<div class="app__item">4</div>
<div class="app__item">5</div>
<div class="app__item">6</div>
<div class="app__item">7</div>
<div class="app__item">8</div>
<div class="app__item">9</div>
<div class="app__item">10</div>
<div class="app__item">
<button>search</button>
</div>
</div>

Thank #Dacre Denny for giving me inspiration. Finally, I got it.
.app {
background:pink;
width: 90vw;
padding:5px;
display:grid;
grid-template-columns: repeat(auto-fit,200px);
justify-content:space-evenly;
grid-gap: 5px;
}
.app__item {
background: lightblue;
width: 200px;
height: 40px;
}
.app__item--size2 {
/* Cause top left cell to occupy two rows */
grid-row: 1 / 3;
height:100%;
}
.app__item:last-child {
grid-column-end: -1
}
<div class="app">
<div class="app__item app__item--size2">1</div>
<div class="app__item">2</div>
<div class="app__item">3</div>
<div class="app__item">4</div>
<div class="app__item">5</div>
<div class="app__item">6</div>
<div class="app__item">7</div>
<div class="app__item">8</div>
<div class="app__item">9</div>
<div class="app__item">10</div>
<div class="app__item">
<button>search</button>
</div>
</div>
See this gif when viewport is changing.

Slide down and up function problem with flex: 1

$(".div3Btn").click(function() {
$(".div2").show("slide", {
direction: "up"
}, 5000);
});
.div1 {
display: flex;
height: 100%;
flex-direction: column;
background-color: #919191;
}
.div2 {
display: flex;
overflow-y: auto;
flex: 1;
height: 500px;
background-color: #a8d810;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="div1">
<div class="div2" style="display: none;">hjghjgjghj</div>
<div class="div3">
<button class="div3Btn">Click me!</button>
</div>
</div>
I have a question about using the show()/hide() function with time and direction. As the above snippet shows, if the button was clicked, it will immediately jump to the bottom, but not following the div1 to slide down. Then how can I fix it if I want to use that function?
$(".div3Btn").click(function() {
$(".div2").slideToggle(5000);
});
.div1 {
display: flex;
height: 100%;
flex-direction: column;
background-color: #919191;
}
.div2 {
display: flex;
overflow-y: auto;
flex: 1;
height: 500px;
background-color: #a8d810;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="div1">
<div class="div2" style="display: none;">hjghjgjghj</div>
<div class="div3">
<button class="div3Btn">Click me!</button>
</div>
</div>
(The problem is quite similar to using Firefox to run the link function)
Another question about slide down and up is when I use flex: 1 for some divs, and then use the slideToggle() function, it does not have any slide down or up animation of the div. How to fix it if I must use flex: 1 for divs?

I think you've formatted the .show() function wrong. Try .show( duration [, easing ] [, complete ] )
$(".div3Btn").click(function() {
$(".div2").show(5000, "swing", function() {
// Animation complete.
});
});
.div1 {
display: flex;
height: 100%;
flex-direction: column;
background-color: #919191;
}
.div2 {
display: flex;
overflow-y: auto;
flex: 1;
height: 500px;
background-color: #a8d810;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="div1">
<div id="div2" class="div2" style="display: none;">hjghjgjghj</div>
<div class="div3">
<button id="div3Btn" class="div3Btn">Click me!</button>
</div>
</div>

How to create 2 divs with equal height without bootstrap or jquery

I am trying to write a code is CSS and normal javascript but it won't work. Here is my code (HTML and CSS).
.wrapper{
height: 100%;
margin: 1.5rem 0 0 0;
display: flex;
}
.first{
vertical-align: top;
display: inline-block;
margin-right: 2rem;
flex: 1;
}
.second{
vertical-align:top;
display: inline-block;
flex: 1;
}
<div class="wrapper">
<div class="first">
<div class="times">
<div><h1>TIMES</h1><br></div>
<div class="space">
<h2>TIMES</h2>
<p>GESLOTEN</p>
</div>
<div class="space">
<h2>Dinsdag - Zaterdag</h2>
<p>09:30 UUR - 18:00 UUR</p>
</div>
</div>
</div>
<div class="second">
<div class="welcome">
<div><h1>WELKOM</h1></div>
<div><p>TEKST</p></div>
</div>
</div>
</div>
I have tried everything, at least I think I have.
The problem is that I can't fix this in CSS but I tried Java.
Still no success. Can someone please explain why I can't get it the same height.
It's a school project and I need to make a website from scratch.
Here is my full website source code: https://codepen.io/crosso_7/pen/VERrvQ

Both first and second divs are actually the same height - I just copied your snippet and applied a border around each div to see the issue and both divs are equal.
.wrapper{
height: 100%;
margin: 1.5rem 0 0 0;
display: flex;
}
.first{
vertical-align: top;
display: inline-block;
margin-right: 2rem;
flex: 1;
border: solid 1px blue;
}
.second{
vertical-align:top;
display: inline-block;
flex: 1;
border: solid 1px red;
}
<div class="wrapper">
<div class="first">
<div class="times">
<div><h1>TIMES</h1><br></div>
<div class="space">
<h2>TIMES</h2>
<p>GESLOTEN</p>
</div>
<div class="space">
<h2>Dinsdag - Zaterdag</h2>
<p>09:30 UUR - 18:00 UUR</p>
</div>
</div>
</div>
<div class="second">
<div class="welcome">
<div><h1>WELKOM</h1></div>
<div><p>TEKST</p></div>
</div>
</div>
</div>

You can do it using flexbox. Something like this code snippet.
.wrapper {
display: flex;
justify-content: space-between;
}
.wrapper div {
background: #000;
color: #fff;
flex: 1;
margin: 10px;
justify-content: center;
}
<div class='wrapper'>
<div>
<h1>1</h1>
<h2>asasasa</h2>
</div>
<div>2</div>
</div>

Is the first div the one thats higher? It's probably created by the padding from first div content vs seconds less content.
May have to set first and second div with a px or % height which are the same to make it equal.

Try using the code below in your .first and .second divs
flex: 1;
display: flex;

Set width of child div in flex container

I have 4 divs with the class .piece-slide that horizontally scroll across the page within the the div #work, which is a flex element. Within the third .piece-slide div the 3 nested elements are absolutely positioned, this renders the width of the third .piece-slide div to 0, so now I want to programmatically set the width of the third .piece-slide div so that it covers the 3 nested elements.
For some reason I am unable to set this width through CSS. I have also tried through jQuery. It would be much appreciated if some pointed me in the right direction as how to rectify this. Here is a jsfiddle as well as the embedded code below.
$("#third-div").outerWidth("100vw");
#wrapper {
display: flex;
flex-direction: column;
height: 100vh;
}
.content {
flex: 1;
}
#work {
height: 100%;
overflow-x: scroll;
display: flex;
background-color: red;
}
.piece-slide {
display: flex;
align-items: center;
position: relative;
padding-right: 5em;
box-sizing: border-box;
border-right: 1px solid black;
}
.piece {
width: 25vw;
margin: 10px;
}
.piece img {
max-width: 100%;
}
#third-div {
/* D0ES NOT WORK */
width: 100vw;
background-color: green;
}
#third-div a {
position: absolute;
}
#third-div a:nth-child(1) {
top: 0;
left: 0;
}
#third-div a:nth-child(2) {
top: 25vw;
left: 25vw;
}
#third-div a:nth-child(3) {
left: 60vw;
}
<div id="wrapper">
<div class="content">
<div id="work">
<div class="piece-slide">
<a class="piece">
<img src="https://athlonecommunityradio.ie/wp-content/uploads/2017/04/placeholder.png">
</a>
</div>
<div class="piece-slide">
<a class="piece">
<img src="https://dummyimage.com/hd1080https://dummyimage.com/hd1080">
</a>
<a class="piece">
<img src="https://dummyimage.com/hd1080https://dummyimage.com/hd1080">
</a>
</div>
<!-- THIRD DIV WHERE WIDTH SHOULD BE SET -->
<div id="third-div" class="piece-slide">
<a class="piece" num="1">
Nested Element 1<img src="http://i.stack.imgur.com/yZlqh.png">
</a>
<a class="piece" num="2">
Nested Element 2<img src="http://www.jennybeaumont.com/wp-content/uploads/2015/03/placeholder.gif">
</a>
<a class="piece" num="3">
Nested Element 3<img src="http://suplugins.com/podium/images/placeholder-02.jpg">
</a>
</div>
<div class="piece-slide">
<a class="piece">
<img src="https://athlonecommunityradio.ie/wp-content/uploads/2017/04/placeholder.png">
</a>
</div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Try to remove
flex-direction: column;
from #wrapper.
Or change it to
flex-direction: row;