How can I prevent a child div with scrollbars and flex:1 from exceeding the height of its parent flexbox in Firefox? It works correctly in Chrome.
CodePen link (if you prefer it to Stack Overflow snippets):
https://codepen.io/garyapps/pen/ZMNVJg
Details:
I have a flex container of fixed height. It has a flex-direction:column setting, and it contains multiple childen divs which will get vertically stacked. One of the child divs is given a flex:1 property, whereas others are given fixed heights.
My expectation is that the child div with the flex:1 property will expand to fill the remaining vertical space. This works as expected.
I have also given the child div an overflow-y:scroll property, so that if the content within it exceeds its height, scrollbars appear. This works fine in Chrome. In Firefox however, this child's height increases, exceeding its parent div.
In Chrome:
In Firefox:
As you see in the screenshot, I have two occurrences of this issue, once in the panel on the left, and the other in the panel on the right. In Chrome, the height of the child div remains constant, scrollbars appear, and the height of the parent does not get exceeded. In Firefox scrollbars do not appear, and the height of the child div increases and exceeds its parent.
I have looked at a few other similar questions on SO, and in many cases setting a min-height:0 property solved the problem in Firefox. However I have tried adding min-height:0 to parents, children, both parents and children, and had no luck.
Please run the code snippet below in both Chrome and Firefox to see the difference in the two browsers.
I would appreciate any advice on how to prevent child div from growing.
(Note that Bootstrap 4 is being used. The code snippet references the bootstrap 4 .css file CDN)
Code Snippet:
.body-content {
height: 300px;
max-height:100%;
border: 3px dashed purple;
display:flex;
flex-direction: column;
}
#messagescontainerrow {
flex: 1;
border: 5px double black;
}
#leftdiv {
display:flex;
flex-direction:column;
border: 1px solid green;
}
#messagetools {
height: 50px;
background-color: cornsilk;
}
#messagelist {
flex:1;
overflow-y: scroll;
background-color:whitesmoke;
}
#rightdiv {
display:flex;
flex-direction:column;
border: 1px solid blue;
}
#messagesenderspane {
width: 100%;
height: 50px;
background-color: lemonchiffon
}
#messagecontents {
flex: 1;
overflow-y: scroll;
width: 100%;
border: 1px solid blue;
background-color: aliceblue;
}
#messagesend {
width: 100%;
height: 70px;
background-color: whitesmoke;
}
<html>
<head>
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.2/css/bootstrap.min.css" rel="stylesheet"/>
</head>
<body>
<div class="container body-content">
<div class="row" id="messagescontainerrow">
<div class="col-5" id="leftdiv">
<div id="messagetools">
<input type="button" id="newbutton" value="My Button" />
</div>
<div id="messagelist">
<h4>Chat 1</h4>
<h4>Chat 2</h4>
<h4>Chat 3</h4>
<h4>Chat 4</h4>
<h4>Chat 5</h4>
<h4>Chat 6</h4>
<h4>Chat 7</h4>
<h4>Chat 8</h4>
</div>
</div>
<div class="col-7" id="rightdiv">
<div id="messagesenderspane">
Chat 3
</div>
<div id="messagecontents">
<h4>line 1</h4>
<h4>line 2</h4>
<h4>line 3</h4>
<h4>line 4</h4>
<h4>line 5</h4>
<h4>line 6</h4>
<h4>line 7</h4>
</div>
<div id="messagesend">
<textarea id="sendbox"></textarea>
<input type="button" id="sendbutton" value="Send" />
</div>
</div>
</div>
</div>
</body>
</html>
Short Answer
Instead of flex: 1, use flex: 1 1 1px.
Make these two adjustments in your code:
#messagelist {
/* flex:1; */
flex: 1 1 1px; /* new */
}
#messagecontents {
/* flex:1; */
flex: 1 1 1px; /* new */
}
revised codepen
Explanation
In most cases, as you have noted, adding min-height: 0 to flex items in a column-direction container is enough to correct the problem.
In this case, however, there's an additional obstacle: flex-basis.
You're applying the following rule to flex items #messagelist and #messagecontents: flex: 1.
This is a shorthand rule that breaks down to:
flex-grow: 1
flex-shrink: 1
flex-basis: 0
(source: https://www.w3.org/TR/css-flexbox-1/#flex-common)
2019 UPDATE: Since the posting of this answer in 2018, it appears that Chrome's behavior has changed and is now uniform with Firefox and Edge. Please keep that in mind as you read the rest of this answer.
In Chrome, flex-basis: 0 is enough to trigger an overflow, which generates the scrollbars. (2019 update: This may no longer be the case.)
In Firefox and Edge, however, a zero flex-basis is insufficient. This is probably the more correct behavior in terms of standards compliance as MDN states:
In order for overflow to have an effect, the block-level container must have either a set height (height or max-height) or white-space set to nowrap.
Well, flex-basis: 0 meets none of those conditions, so an overflow condition should not occur. Chrome has probably engaged in an intervention (as they often do).
An intervention is when a user agent decides to deviate slightly from a standardized behavior in order to provide a greatly enhanced user experience.
To meet the "standardized behavior", which would enable an overflow to occur in Firefox and Edge, give flex-basis a fixed height (even if it's just 1px).
I am marking Michael_B's answer as the correct one, since it is a valid solution along with an explanation. In addition here is another solution I came up with, which does not require modifying the flex-basis:
#messagescontainerrow {
flex: 1;
min-height: 0; /* ADDED THIS. */
border: 5px double black;
}
#leftdiv {
display:flex;
flex-direction:column;
max-height: 100%; /* ADDED THIS */
border: 1px solid green;
}
#rightdiv {
display:flex;
flex-direction:column;
max-height: 100%; /* ADDED THIS */
border: 1px solid blue;
}
Explanation:
As per the current Flexbox specification https://www.w3.org/TR/css-flexbox-1/#min-size-auto
In general, the automatic minimum size of a flex item is the smaller
of its content size and its specified size. However, if the box has an
aspect ratio and no specified size, its automatic minimum size is the
smaller of its content size and its transferred size. If the box has
neither a specified size nor an aspect ratio, its automatic minimum
size is the content size.
So, by default #messagescontainerrow was taking on a minimum height based on its contents, rather than respecting the height of its parent flexbox. This behavior can be overridden by setting min-height:0.
By making this change one sees what is displayed in the following image; note that #messagescontainerrow - the one with the double line border - is now the same height as its parent - the one with the purple dashed border.
(Note that the more recent draft specification, found here - https://drafts.csswg.org/css-flexbox/#min-size-auto - says "for scroll containers the automatic minimum size is zero". So in future we might not need to do this).
What remains now is the issue of its children, #leftdiv and #rightdiv, overflowing its borders. As Michael_B pointed out, overflow requires a height or max-height property to be present. So the next step is to add max-height: 100% to both #leftdiv and #rightdiv, so that the overflow-y:scroll property of their children gets triggered.
Here is the result:
Related
I've been doing CSS for a while now but couldn't figure out what's going here. Feeling really dumb :) Could you explain the behaviour?
.parent {
display:inline-block;
}
.child {
border: 2px solid red;
padding: 20px; /* this works as expected */
padding: 20%;
box-sizing: border-box; /* makes no difference */
}
<div class="parent">
<div class="child">CSSisAwesome</div>
</div>
You are facing a cyclic calculation due to the use of percentage value. The parent is an inline-block element so its width is defined by its content and that same content is using a percentage value so the content need a reference for that percentage which is the width of the parent. You have a cycle.
In such case, the browser will first ignore the padding to define the parent width and then calculate the padding BUT we don't get to calculate the parent width again because will have an infinite loop.
Check this:
.parent {
display: inline-block;
}
.child {
border: 2px solid red;
}
<div class="parent">
<div class="child">CSSisAwesome</div>
</div>
<br>
<br>
<div class="parent">
<div class="child" style="padding: 20%;">CSSisAwesome</div>
</div>
Note how in both cases, the width of the parent is the same and that width is defined by the content. The padding is added later and create an overflow.
You can find mode detail in the Specification
Sometimes the size of a percentage-sized box’s containing block depends on the intrinsic size contribution of the box itself, creating a cyclic dependency.
Related questions:
Why does percentage padding break my flex item?
CSS Grid - unnecessary word break
How percentage truly works compared to other units in different situations
As seen in this CSSTricks article, padding using percentage units is in relation to the parent container, not the content within the element. The 20% padding you're setting in your code snippet is in relation to the .parent div's dimensions, not in relation to the content within the .child div.
If you are using % as a unit, Parent should have fixed width and height
I want to have a square div inside a flexbox. So I use:
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
padding-bottom: 50%;
}
<div class="outer">
<div class="inner">
<a>hehe</a>
</div>
</div>
This works fine in Chrome. But in Firefox, the parent squeezes to just one line.
How do I solve this in Firefox? I use version 44.
You can also view the code at https://jsbin.com/lakoxi/edit?html,css
2018 Update
The flexbox specification has been updated.
4.2. Flex Item Margins and Paddings
Percentage margins and paddings on flex items, like those on block
boxes, are resolved against the inline size of their containing block,
e.g. left/right/top/bottom percentages all resolve against their
containing block’s width in horizontal writing modes.
Original Answer - applies to FF and Edge versions released before 2018
From the flexbox specification:
Authors should avoid using percentages in paddings or margins on flex items entirely, as they will get different behavior in different browsers.
Here's some more:
4.2. Flex Item Margins and Paddings
Percentage margins and paddings on flex items can be resolved against either:
their own axis (left/right percentages resolve against width, top/bottom resolve against height), or,
the inline axis (left/right/top/bottom percentages all resolve against width)
A User Agent must choose one of these two behaviors.
Note: This variance sucks, but it accurately captures the current state of the world (no consensus among implementations, and no consensus within the CSSWG). It is the CSSWG’s intention that browsers will converge on one of the behaviors, at which time the spec will be amended.
In addition to Michael_B's answer, here is a possible workaround.
When using percent we often relate that to the viewport width, so with that in mind, viewport units vw/vh can be an option, since it works similar (responsive).
Stack snippet
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
padding-bottom: 50vw;
}
<div class="outer">
<div class="inner">
<a>hehe</a>
</div>
</div>
Updated based on a comment
If a square is a must, and viewport units or script can't be used, here is another trick using a dummy image.
Note, as image also a SVG or a Base64 could be used as a datauri to save an extra round trip to the server
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
}
.inner img {
display: block;
width: 100%;
visibility: hidden;
}
<div class="outer">
<div class="inner">
<img src="http://placehold.it/10" alt="">
</div>
</div>
How can I prevent a child div with scrollbars and flex:1 from exceeding the height of its parent flexbox in Firefox? It works correctly in Chrome.
CodePen link (if you prefer it to Stack Overflow snippets):
https://codepen.io/garyapps/pen/ZMNVJg
Details:
I have a flex container of fixed height. It has a flex-direction:column setting, and it contains multiple childen divs which will get vertically stacked. One of the child divs is given a flex:1 property, whereas others are given fixed heights.
My expectation is that the child div with the flex:1 property will expand to fill the remaining vertical space. This works as expected.
I have also given the child div an overflow-y:scroll property, so that if the content within it exceeds its height, scrollbars appear. This works fine in Chrome. In Firefox however, this child's height increases, exceeding its parent div.
In Chrome:
In Firefox:
As you see in the screenshot, I have two occurrences of this issue, once in the panel on the left, and the other in the panel on the right. In Chrome, the height of the child div remains constant, scrollbars appear, and the height of the parent does not get exceeded. In Firefox scrollbars do not appear, and the height of the child div increases and exceeds its parent.
I have looked at a few other similar questions on SO, and in many cases setting a min-height:0 property solved the problem in Firefox. However I have tried adding min-height:0 to parents, children, both parents and children, and had no luck.
Please run the code snippet below in both Chrome and Firefox to see the difference in the two browsers.
I would appreciate any advice on how to prevent child div from growing.
(Note that Bootstrap 4 is being used. The code snippet references the bootstrap 4 .css file CDN)
Code Snippet:
.body-content {
height: 300px;
max-height:100%;
border: 3px dashed purple;
display:flex;
flex-direction: column;
}
#messagescontainerrow {
flex: 1;
border: 5px double black;
}
#leftdiv {
display:flex;
flex-direction:column;
border: 1px solid green;
}
#messagetools {
height: 50px;
background-color: cornsilk;
}
#messagelist {
flex:1;
overflow-y: scroll;
background-color:whitesmoke;
}
#rightdiv {
display:flex;
flex-direction:column;
border: 1px solid blue;
}
#messagesenderspane {
width: 100%;
height: 50px;
background-color: lemonchiffon
}
#messagecontents {
flex: 1;
overflow-y: scroll;
width: 100%;
border: 1px solid blue;
background-color: aliceblue;
}
#messagesend {
width: 100%;
height: 70px;
background-color: whitesmoke;
}
<html>
<head>
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.2/css/bootstrap.min.css" rel="stylesheet"/>
</head>
<body>
<div class="container body-content">
<div class="row" id="messagescontainerrow">
<div class="col-5" id="leftdiv">
<div id="messagetools">
<input type="button" id="newbutton" value="My Button" />
</div>
<div id="messagelist">
<h4>Chat 1</h4>
<h4>Chat 2</h4>
<h4>Chat 3</h4>
<h4>Chat 4</h4>
<h4>Chat 5</h4>
<h4>Chat 6</h4>
<h4>Chat 7</h4>
<h4>Chat 8</h4>
</div>
</div>
<div class="col-7" id="rightdiv">
<div id="messagesenderspane">
Chat 3
</div>
<div id="messagecontents">
<h4>line 1</h4>
<h4>line 2</h4>
<h4>line 3</h4>
<h4>line 4</h4>
<h4>line 5</h4>
<h4>line 6</h4>
<h4>line 7</h4>
</div>
<div id="messagesend">
<textarea id="sendbox"></textarea>
<input type="button" id="sendbutton" value="Send" />
</div>
</div>
</div>
</div>
</body>
</html>
Short Answer
Instead of flex: 1, use flex: 1 1 1px.
Make these two adjustments in your code:
#messagelist {
/* flex:1; */
flex: 1 1 1px; /* new */
}
#messagecontents {
/* flex:1; */
flex: 1 1 1px; /* new */
}
revised codepen
Explanation
In most cases, as you have noted, adding min-height: 0 to flex items in a column-direction container is enough to correct the problem.
In this case, however, there's an additional obstacle: flex-basis.
You're applying the following rule to flex items #messagelist and #messagecontents: flex: 1.
This is a shorthand rule that breaks down to:
flex-grow: 1
flex-shrink: 1
flex-basis: 0
(source: https://www.w3.org/TR/css-flexbox-1/#flex-common)
2019 UPDATE: Since the posting of this answer in 2018, it appears that Chrome's behavior has changed and is now uniform with Firefox and Edge. Please keep that in mind as you read the rest of this answer.
In Chrome, flex-basis: 0 is enough to trigger an overflow, which generates the scrollbars. (2019 update: This may no longer be the case.)
In Firefox and Edge, however, a zero flex-basis is insufficient. This is probably the more correct behavior in terms of standards compliance as MDN states:
In order for overflow to have an effect, the block-level container must have either a set height (height or max-height) or white-space set to nowrap.
Well, flex-basis: 0 meets none of those conditions, so an overflow condition should not occur. Chrome has probably engaged in an intervention (as they often do).
An intervention is when a user agent decides to deviate slightly from a standardized behavior in order to provide a greatly enhanced user experience.
To meet the "standardized behavior", which would enable an overflow to occur in Firefox and Edge, give flex-basis a fixed height (even if it's just 1px).
I am marking Michael_B's answer as the correct one, since it is a valid solution along with an explanation. In addition here is another solution I came up with, which does not require modifying the flex-basis:
#messagescontainerrow {
flex: 1;
min-height: 0; /* ADDED THIS. */
border: 5px double black;
}
#leftdiv {
display:flex;
flex-direction:column;
max-height: 100%; /* ADDED THIS */
border: 1px solid green;
}
#rightdiv {
display:flex;
flex-direction:column;
max-height: 100%; /* ADDED THIS */
border: 1px solid blue;
}
Explanation:
As per the current Flexbox specification https://www.w3.org/TR/css-flexbox-1/#min-size-auto
In general, the automatic minimum size of a flex item is the smaller
of its content size and its specified size. However, if the box has an
aspect ratio and no specified size, its automatic minimum size is the
smaller of its content size and its transferred size. If the box has
neither a specified size nor an aspect ratio, its automatic minimum
size is the content size.
So, by default #messagescontainerrow was taking on a minimum height based on its contents, rather than respecting the height of its parent flexbox. This behavior can be overridden by setting min-height:0.
By making this change one sees what is displayed in the following image; note that #messagescontainerrow - the one with the double line border - is now the same height as its parent - the one with the purple dashed border.
(Note that the more recent draft specification, found here - https://drafts.csswg.org/css-flexbox/#min-size-auto - says "for scroll containers the automatic minimum size is zero". So in future we might not need to do this).
What remains now is the issue of its children, #leftdiv and #rightdiv, overflowing its borders. As Michael_B pointed out, overflow requires a height or max-height property to be present. So the next step is to add max-height: 100% to both #leftdiv and #rightdiv, so that the overflow-y:scroll property of their children gets triggered.
Here is the result:
I want to have a square div inside a flexbox. So I use:
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
padding-bottom: 50%;
}
<div class="outer">
<div class="inner">
<a>hehe</a>
</div>
</div>
This works fine in Chrome. But in Firefox, the parent squeezes to just one line.
How do I solve this in Firefox? I use version 44.
You can also view the code at https://jsbin.com/lakoxi/edit?html,css
2018 Update
The flexbox specification has been updated.
4.2. Flex Item Margins and Paddings
Percentage margins and paddings on flex items, like those on block
boxes, are resolved against the inline size of their containing block,
e.g. left/right/top/bottom percentages all resolve against their
containing block’s width in horizontal writing modes.
Original Answer - applies to FF and Edge versions released before 2018
From the flexbox specification:
Authors should avoid using percentages in paddings or margins on flex items entirely, as they will get different behavior in different browsers.
Here's some more:
4.2. Flex Item Margins and Paddings
Percentage margins and paddings on flex items can be resolved against either:
their own axis (left/right percentages resolve against width, top/bottom resolve against height), or,
the inline axis (left/right/top/bottom percentages all resolve against width)
A User Agent must choose one of these two behaviors.
Note: This variance sucks, but it accurately captures the current state of the world (no consensus among implementations, and no consensus within the CSSWG). It is the CSSWG’s intention that browsers will converge on one of the behaviors, at which time the spec will be amended.
In addition to Michael_B's answer, here is a possible workaround.
When using percent we often relate that to the viewport width, so with that in mind, viewport units vw/vh can be an option, since it works similar (responsive).
Stack snippet
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
padding-bottom: 50vw;
}
<div class="outer">
<div class="inner">
<a>hehe</a>
</div>
</div>
Updated based on a comment
If a square is a must, and viewport units or script can't be used, here is another trick using a dummy image.
Note, as image also a SVG or a Base64 could be used as a datauri to save an extra round trip to the server
.outer {
display: flex;
width: 100%;
background: blue;
}
.inner {
width: 50%;
background: yellow;
}
.inner img {
display: block;
width: 100%;
visibility: hidden;
}
<div class="outer">
<div class="inner">
<img src="http://placehold.it/10" alt="">
</div>
</div>
I'm trying to create a flexible layout in CSS3 with 3 boxes stacked on each other. The boxes are siblings and thus have the same parent element. The height of the first box must fit its content. The height of the following two boxes shall grow to fit their respective content until they're about to overflow their parent. In that case, they shall shrink so that they don't overflow.
The problem is that I can't figure out how to prevent one of the shrinking boxes from becoming crushed if its content is small in relation to the other shrinking box. I want those boxes to shrink down to a certain point where they won't shrink anymore – let's say the equivalent of two rows of text for example. Setting min-width isn't an option because I don't want the boxes to be taller than their content in case the content is only one row for example. If any of the boxes has come to the point where it shall not shrink anymore and the parent can't hold them without overflowing, the parent shall get a scrollbar.
I don't know the content in advance so the layout has to be dynamic. I want to solve this only with CSS, if possible.
Here's an example of the problem where box3 is too small:
p {
margin: 0;
}
.container, .box {
border: 1px solid black;
}
.box {
background-color: white;
margin: 1em;
overflow: auto;
}
#container {
background-color: yellow;
display: flex;
flex-direction: column;
height: 15em;
overflow: auto;
}
#box1 {
flex: 0 0 auto;
}
#box2 {
}
#box3 {
}
<div id="container" class="container">
<div id="box1" class="box">
<p>◼</p>
</div>
<div id="box2" class="box">
<p>◼◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◻◻◻◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◻◻◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◻◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◻◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◻◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◻◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◻◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◻◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◻◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◻◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◻◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◼◻◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◻◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◻◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◻</p>
<p>◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼</p>
</div>
<div id="box3" class="box">
<p>◼◻◻</p>
<p>◼◼◻</p>
<p>◼◼◼</p>
</div>
</div>
IF I understand your question correctly, the flex-shrink property should be what you are looking for.
Set #box1 to flex-shrink: 0
Set #box2 to flex-shrink: 1
Set #box3 to flex-shrink: 1