Why Does The overflow-y Property Not Work With Percent Height - css

I'm trying to use percentage height with overflow-y:auto; and instead of creating a scroll bar on the side of the div, it's using the page scroll bar.
Here's an example of want I'm getting at: http://jsfiddle.net/hmwe2jty/
Is it possible to use this property with percent height?

TL;DR Use the viewport height/width instead of a percentage. Change 100% to 100vh, and you're done!
EDIT:
The percentages take the precentage of the parent element. For example:
console.log("Parent's width: " + document.getElementById("parent").offsetWidth);
console.log("Child's width: " + document.getElementById("child").offsetWidth);
#parent {
background: yellow;
width: 500px;
height: 150px;
}
#child {
background: orange;
width: 50%;
height: 100px;
}
<div id="parent">
<div id="child">
I am 250px wide!
</div>
</div>
The new CSS3 viewport units use the user's viewport as a base. For example:
console.log("Parent's width: " + document.getElementById("parent").offsetWidth);
console.log("Child's width: " + document.getElementById("child").offsetWidth);
#parent {
background: yellow;
width: 500px;
height: 150px;
}
#child {
background: orange;
width: 50vw;
height: 100px;
}
<div id="parent">
<div id="child">
My width is 50% of the user's viewport, regardless of the size of my parent!
</div>
</div>
Because the body element is a bit weird, it's default behaviour is to shrink to fit is contents. So:
body {
background: yellow;
border: 1px solid red;
}
The body element wraps around it contents, <br>
but the backgound just ignores this behaviour.
So, since the parent element is the body, you will need to use the new vw and vh units. Read a article on CSS Tricks
EDIT 2:
Another way to choose the viewport as parent would be to make the element's position either fixed or absolute. In that instance the parent would become the viewport, thus giving you the needed value.

use this css for div which height must dimensioned in percents of parent element:
.child {
position: absolute;
top: 10px;
bottom: 0px;
}

It is considering 100% of the parent, which is the body. Hence it occupies the height of complete space available. Specify height a lesser amount in % rather than 100 (if you specifically prefer percent). It is upto you what you chose.

Related

button height in percent makes it flat [duplicate]

I am trying to set a <div> to a certain percentage height in CSS, but it just remains the same size as the content inside it. When I remove the HTML 5 <!DOCTYTPE html> however, it works, the <div> taking up the whole page as desired. I want the page to validate, so what should I do?
I have this CSS on the <div>, which has an ID of page:
#page {
padding: 10px;
background-color: white;
height: 90% !important;
}
I am trying to set a div to a certain percentage height in CSS
Percentage of what?
To set a percentage height, its parent element(*) must have an explicit height. This is fairly self-evident, in that if you leave height as auto, the block will take the height of its content... but if the content itself has a height expressed in terms of percentage of the parent you've made yourself a little Catch 22. The browser gives up and just uses the content height.
So the parent of the div must have an explicit height property. Whilst that height can also be a percentage if you want, that just moves the problem up to the next level.
If you want to make the div height a percentage of the viewport height, every ancestor of the div, including <html> and <body>, have to have height: 100%, so there is a chain of explicit percentage heights down to the div.
(*: or, if the div is positioned, the ‘containing block’, which is the nearest ancestor to also be positioned.)
Alternatively, all modern browsers and IE>=9 support new CSS units relative to viewport height (vh) and viewport width (vw):
div {
height:100vh;
}
See here for more info.
You need to set the height on the <html> and <body> elements as well; otherwise, they will only be large enough to fit the content. For example:
<!DOCTYPE html>
<title>Example of 100% width and height</title>
<style>
html, body { height: 100%; margin: 0; }
div { height: 100%; width: 100%; background: red; }
</style>
<div></div>
bobince's answer will let you know in which cases "height: XX%;" will or won't work.
If you want to create an element with a set ratio (height: % of it's own width), use the aspect-ratio property. Make sure height is not explicitly set on the element for it to work. https://developer.mozilla.org/en-US/docs/Web/CSS/aspect-ratio
.square {
width: 100%;
height: unset;
aspect-ratio: 1 / 1;
}
Historically, the best way to do this was to set the height using padding-bottom. Example for square:
<div class="square-container">
<div class="square-content">
<!-- put your content in here -->
</div>
</div>
.square-container { /* any display: block; element */
position: relative;
height: 0;
padding-bottom: 100%; /* of parent width */
}
.square-content {
position: absolute;
left: 0;
top: 0;
height: 100%;
width: 100%;
}
The square container will just be made of padding, and the content will expand to fill the container. Long article from 2009 on this subject: http://alistapart.com/article/creating-intrinsic-ratios-for-video
In order to use percentage(%), you must define the % of its parent element. If you use body{height: 100%} it will not work because its parent have no percentage in height. In that case in order to work that body height you must add this in html{height:100%}
In other cases to get rid of that defining parent percentage you can use
body{height:100vh}
vh stands for viewport height
You can use 100vw / 100vh. CSS3 gives us viewport-relative units. 100vw means 100% of the viewport width. 100vh; 100% of the height.
<div style="display:flex; justify-content: space-between;background-color: lightyellow; width:100%; height:85vh">
<div style="width:70%; height: 100%; border: 2px dashed red"></div>
<div style="width:30%; height: 100%; border: 2px dashed red"></div>
</div>
Sometimes, you may want to conditionally set the height of a div, such as when the entire content is less than the height of the screen. Setting all parent elements to 100% will cut off content when it is longer than the screen size.
So, the way to get around this is to set the min-height:
Continue to let the parent elements automatically adjust their height
Then in your main div, subtract the pixel sizes of the header and footer div from 100vh (viewport units). In css, something like:
min-height: calc(100vh - 246px);
100vh is full length of the screen, minus the surrounding divs.
By setting min-height and not height, content longer than screen will continue to flow, instead of getting cut off.
With new CSS sizing properties you can get away with not setting exact height on parent. The new block-size and inline-size properties can be used like this:
<!DOCTYPE html>
<style>
#parent {
border: 1px dotted gray;
height: auto; /* auto values */
width: auto;
}
#wrapper {
background-color: violet;
writing-mode: vertical-lr;
block-size: 30%;
inline-size: 70%;
}
#child {
background-color: wheat;
writing-mode: horizontal-tb;
width: 30%; /* set to 100% if you don't want to expose wrapper */
height: 70%; /* none of the parent has exact height set */
}
</style>
<body>
<div id=parent>
<div id=wrapper>
<div id=child>Lorem ipsum dollar...</div>
Resize the browser window in full page mode. I think the values are relative to viewport height and width.
For more info refer: https://www.w3.org/TR/css-sizing-3/
Almost all browsers support it: https://caniuse.com/?search=inline-size

Evaluating percentages to pixels in SASS

Currently, I'm setting a variable to correspond to a circle's width and height, like so:
$circle-diameter: 70%;
.circle {
width: $circle-diameter;
height: $circle-diameter;
}
However, the circle's width becomes 70% of the parent element's width, and the height becomes 70% of the parent element's height, which yields an oval that is wider than it is tall. Ideally, I'd like to convert .circle-diameter to a fixed size and assign the circle's width and height to that fixed size. Is there a solution for this in CSS/SASS?
You can use padding-top instead of height, it will work because padding is relative to parent width.
.circle{
width: 70%;
padding-top: 70%;
/* height: 0; */
}
http://codepen.io/yukulele/pen/PzGgNM
What you are looking for is to have a fixed ratio between width and height. For a circle tho, the width/height ratio is 1. There's a hacky way to accomplish that task. First I'd like to write a css class that always provides us a space that has width/height ratio of 1. To do so:
See Fiddle
Why this works? Because, If you use percentage based units on padding, It always be relative to element's width. See reference
Next I always like to use absolute hack to provide myself a workaround in that nicely 1/1 ratio square that we've create.
See Fiddle 2
Using position: absolute for our own good, we've created a element that has a fixed ratio and has a working width/height properties.
After It depends on what you need to do. In your case I've created a nice circle for to examine the situation.
See Fiddle 3
Working source code
**Css**
.ratio-1 {
position: relative;
width: 100%;
padding-top: 100%;
background-color: silver;
}
.im-something-has-some-width {
width: 200px;
border: 3px solid lime;
}
.space-provider {
position: absolute;
left: 0;
right: 0;
top: 0;
bottom: 0;
}
.yay-i-have-a-square-field {
// lets use it for our own goods!
width: 100%;
height: 100%;
background-color: skyblue;
border-radius: 50%;
}
Html
<div class="im-something-has-some-width">
<div class="ratio-1">
<div class="space-provider">
<div class="yay-i-have-a-square-field">
</div>
</div>
</div>
</div>

Maintain div aspect ratio according to height

I need to maintain the width of an element as a percentage of its height. So as the height changes, the width is updated.
The opposite is achievable by using a % value for padding-top, but padding-left as a percentage will be a percentage of the width of an object, not its height.
So with markup like this:
<div class="box">
<div class="inner"></div>
</div>
I'd like to use something like this:
.box {
position: absolute;
margin-top: 50%;
bottom: 0;
}
.inner {
padding-left: 200%;
}
To ensure the box's aspect ratio is maintained according to it's height. The height is fluid because of it's % margin - as the window's height changes, the box's height will too.
I know how to achieve this with JavaScript, just wondering if there's a clean CSS-only solution?
You can use an image that has the desired proportions as to help with proportional sizing (images can be scaled proportionally by setting one dimension to some value and other to auto). The image does not have to be visible, but it must occupy space.
.box {
position: absolute;
bottom: 0;
left: 0;
height: 50%;
}
.size-helper {
display: block;
width: auto;
height: 100%;
}
.inner {
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
background: rgba(255, 255, 153, .8);
}
<div class="box">
<img class="size-helper" src="//dummyimage.com/200x100/999/000" width="200" height="100">
<div class="inner">
1. box has fluid height<br>
2. img has 2:1 aspect ratio, 100% height, auto width, static position<br>
2.1 it thus maintains width = 200% of height<br>
2.2 it defines the dimensions of the box<br>
3. inner expands as much as box
</div>
</div>
In the above example, box, inner and helper are all same size.
You can use vh units for both height and width of your element so they both change according to the viewport height.
vh
1/100th of the height of the viewport. (MDN)
DEMO
.box {
position: absolute;
height:50vh;
width:100vh;
bottom: 0;
background:teal;
}
<div class="box"></div>
There is another, more efficient way to achieve constant aspect ratio according to height.
You can place an empty svg so you dont have to load an external image.
HTML code:
<svg xmlns="http://www.w3.org/2000/svg"
height="100"
width="200"
class='placeholder-svg'
/>
CSS code:
.placeholder-svg {
width: auto;
height: 100%;
}
Change width/height to achieve desired aspect ratio.
Keep in mind, the svg might overflow.
http://www.w3.org/2000/svg is just a namespace. It doesn't load anything.
If you change placeholder-svg class to:
.placeholder-svg {
width: 100%;
height: auto;
}
then height is adjusted according to width.
Demo 1 Width is adjusted according to height and 2:1 aspect ratio.
Demo 2 same as above, but you can resize easily (uses React)
The CSS trick you wrote, works pretty well to keep ratio width / height on an element.
It is based on the padding property that, when its value is in percent, is proportional to parent width, even for padding-top and padding-bottom.
There is no CSS property that could set an horizontal sizing proportionally to the parent height.
So I think there is no clean CSS solution.
As of 2021 there is a property called aspect-ratio.
Most browsers support it
div {
border: 1px solid;
margin: 8px;
}
.box {
width: 100px;
min-height: 100px;
resize: horizontal;
overflow: auto;
}
.inner1 {
aspect-ratio: 1/1;
}
.inner2 {
aspect-ratio: 3/1;
}
<div class="box">
<div class="inner1"></div>
<div class="inner2"></div>
</div>
Run this snippet and resize the outer div manually to see the inner divs behavior
I can't find a pure CSS solution. Here's a solution using CSS Element Queries JavaScript library.
var aspectRatio = 16/9;
var element = document.querySelector('.center');
function update() {
element.style.width = (element.clientHeight * aspectRatio) + 'px';
}
new ResizeSensor(element, update);
update();
CodePen demo!

set div width as a percentage of height

I am trying to set the width of the .full_height_div element using pure css, based on its height. It has to be width-relative-to-height, and not height-relative-to-width. The reason for this is that the parent container (.set_rectangle_height) is already a div with height relative to the page width. Obviously, as the page is resized the divs on the page will resize, so i cannot set a fixed width in px for the .full_height_div child.
So .rectangle and .set_rectangle_height make up the parent container which has a width as a percentage of the page and a height relative to this width. See here for an explanation for this method.
But the problem is that then I want to place a div inside the parent with height: 100% and width relative to this height. The aim is then that I will be able to alter the browser window size and everything will keep its aspect ratio.
here is my failed attempt:
.rectangle
{
position: relative;
width: 30%;/*the outermost div is always a % of the page
width, even while resizing*/
display:inline-block;
background-color: green;
}
.set_rectangle_height
{
padding-bottom: 30%;/*this sets the height of the outermost div
to a ratio of 1:3*/
position: relative;
float: left;
width: 100%;
height: 100%;
}
.full_height_div/*this is the div that i want to have a width relative
to its height*/
{
height: 100%;
width: 20px;/*i will delete this once .square_set_width is working*/
position: absolute;
background-color: red;
}
.square_set_width
{
display: inline-block;
padding-left: 100%; /*i want to use something like this line to set
the width of this div to be equal to .full_height_div's height - ie a 1:1 aspect
ratio, but padding-left does not work :( */
position: relative;
height: 100%;
background-color: blue;
}
<div class='rectangle'>
<div class='set_rectangle_height'>
<div class='full_height_div'>
<div class='square_set_width'></div>
</div>
</div>
</div>
So, this is what the above incorrect markup looks like:
And this is what i want it to look like:
I know I could find the blue square percentage height in javascript, then set the width to be equal to this height, but it would be really handy if there is a pure css fix for what I am trying to do. I will be using this structure a lot and I don't really want to go writing code to resize all the divs on my page.
you have to use javascript for that. If I understood you, you want a perfect blue square. Use
var height = $('.square_set_width').height();
$('.square_set_width').css('width',height);
here is a jsfiddle: http://jsfiddle.net/a8kxu/
Edit: instead of doing padding-bottom: 30% do height: 70% instead. Here is another fiddle: http://jsfiddle.net/a8kxu/1/
Edit #2: Sorry, but you cant use css to do this. Its not powerful enough
If i understand you correctly
you can do
#divID {
width: 75%;
margin-left: auto; // this is used to center the container
margin-right: auto;// this as well
}

Trying to set JScrollPane height to 100% without stretching container?

I have a middle container that takes up whatever vertical space is left on the screen. In it, I placed a Jquery scroller that is currently set to 200px:
.scroll-pane
{
width: 100%;
height: 200px;
overflow: auto;
}
.horizontal-only
{
height: auto;
max-height: 100%;
}
However, if I set .scroll-pane height to 100%, it just removes the scrollbar and stretches the whole page.
See JsFiddle here
How can I stop this? Thanks!
Here is my solution to this problem (jsfiddle). It uses markup like this:
<div id="top">...</div>
<div id="wrapper">
<div id="middle">...</div>
</div>
<div id="bottom">...</div>
The top and bottom divs are position absolutely at the top and bottom, with a width of 100%. The wrapper div has height: 100%, box-sizing: border-box, and top and bottom padding equal to the height of the top and bottom divs, respectively. This causes it to fill the viewport but have padding underneath the top and bottom divs. The middle div has a height of 100% so it fills the content box of the wrapper (i.e., 100% minus the top and bottom paddings). It has position: relative, which leaves you free to use height: 100% on both interior boxes.
Lastly, middleleft is positioned absolutely and middleright has a left margin equal to its width, which causes it to fill the remaining horizontal space.
height: 100% never works like you want it to. The CSS specifications dictate that it must equal the height of the browser window, or the closest parent block-level element with an absolute height specified. That means that this code will should not work as expected:
<!DOCTYPE html>
<html>
<head>
<title>Want the body to fill the page? Too bad!</title>
<style type="text/css">
html, body {
height: 100%;
}
.page {
padding-top: 50px;
box-sizing: border-box;
height: 100%;
}
.header {
margin-top: -50px;
height: 50px;
}
.body {
height: 100%;
background: gray;
}
</style>
</head>
<body>
<div class="page">
<div class="header">
<h1>Too bad!</h1>
</div>
<div class="body">
<p>Hello cruel world...</p>
</div>
</div>
</body>
</html>
However, that works fine in Chrome. Why? I can only assume that Google decided to specifically go against web standards because in this case, the standards make no sense. Why would I want something to be the exact height of the browser window? The only time is a <div> wrapping the whole page; in this case a simple "height is relative to the parent block" rule works just fine without breaking expectations elsewhere.
There is a way around this, though. At least, that's what I wanted to say before I tried this in Firefox too. Another way to get height: 100% (with some restrictions) is with position: absolute. However, it would seem that Firefox isn't respecting position: relative on a display: table-cell element - probably those pesky standards again. Here's the code for this technique anyway, if you are interested:
#wrapper > div > #middleleft {
position: relative;
}
.scroll-pane {
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
}
So what can you do? Well, unfortunately, I don't yet know the answer to that. A kludgy solution would be to have Javascript set the height to an absolute pixel value, and attach an event to window resizing in order to update that height. I'll get back to you if I find a better way.
I'm not sure exactly what your trying to do, but another method would be to set body height to 100%, then set scrollpane to "height: auto". Then for the "top" and "bottom" div's used fixed positioning, plus margin equal to top/bottom height.
body {
height: 100%;
}
.top {
position: fixed;
top: 0;
height: 100px;
}
.middle {
height: auto;
margin: 100px auto;
}
.bottom {
position: fixed;
bottom: 0;
height: 100px;
}
<div class="top">content</div>
<div class="middle">content</div>
<div class="bottom">content</div>
Try that...

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