Develop Reference

Calculating width of scrollbar and using result in calc() css

I want to calculate the width of the scrollbar so that I use the result in a CSS calc() declaration.
At the moment, I assume that the width of the scrollbar is always 17px, like this:
body {
width:calc(100vw - 17px);
}
.container {
max-width:calc(100vw - 17px);
}
The problem with this is when you choose a different browser zoom %, the width of the scrollbar changes. So I want to use the result of the calculation to do something along these lines:
body {
width:calc(100vw - CALCULATED SCROLL-BAR WIDTH);
}
.container {
max-width:calc(100vw - CALCULATED SCROLL-BAR WIDTH);
}
EDIT: I've now solved the problem with the help of this question
The JavaScript used to calculate the scrollbar width (though, I have found you require an interval to get it to autoupdate):
function getScrollbarWidth() {
var outer = document.createElement("div");
outer.style.visibility = "hidden";
outer.style.width = "100px";
outer.style.msOverflowStyle = "scrollbar"; // needed for WinJS apps
document.body.appendChild(outer);
var widthNoScroll = outer.offsetWidth;
// force scrollbars
outer.style.overflow = "scroll";
// add innerdiv
var inner = document.createElement("div");
inner.style.width = "100%";
outer.appendChild(inner);
var widthWithScroll = inner.offsetWidth;
// remove divs
outer.parentNode.removeChild(outer);
return widthNoScroll - widthWithScroll;
}
My code (which is used to embed the result of the function into a CSS calc() declaration).
$('body').css({
'width':'calc(100vw - ' + getScrollbarWidth() + 'px)'
});
$('.container').css({
'max-width':'calc(100vw - ' + getScrollbarWidth() + 'px)'
});

Actually, you can get the scrollbar width just with css and custom properties (and completely without javascript):
body {
--scrollbar-width: calc(100vw - 100%);
}
Then you can use this variable in a child element like this:
.container {
max-width: calc(100vw - var(--scrollbar-width));
}
This is because 100vw is always the inner width of the view, but the 100% of the body does not include the scrollbar.

Expanding jonas_jonas's answer, it can work but if .container must have the same width as the body.
If that's not the case, even so you can make it work with vanilla JS, defining a CSS property like this
document.body.style.setProperty(
"--scrollbar-width",
`${window.innerWidth - document.body.clientWidth}px`
);
And then you can use it in CSS
.container {
max-width: calc(100vw - var(--scrollbar-width));
}

Why you need so much code to do that?
The easy way with plain javascript it's:
$('body').css({
'width':'calc(100vw - ' + (window.innerWidth - document.body.clientWidth) + 'px)'
});

dynamic width of textarea with no-wrap

How can I make a textarea which does not force line wrapping and extends its size to match the contents instead of showing a scroll-bar?
I need a textarea with dynamic width. The width should be the widest line of the textarea. I mean there should be no wrapping and the width should be changed the long a line gets.

Assign an input listener function which compares the scroll width and height against the outer width and height of the element. If they are different then set them as necessary.
For CSS you need white-space:nowrap to stop the lines from wrapping and overflow:hidden to get rid of the scroll bars.
$('.demo').on('input', function(e){
this.style.width = '';
this.style.height = '';
if(this.scrollWidth > this.clientWidth) this.style.width = this.scrollWidth + 'px';
if(this.scrollHeight > this.clientHeight) this.style.height = this.scrollHeight + 'px';
})
.demo {
white-space: nowrap;
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<textarea class="demo"></textarea>

Insert inline element and animate shift to left

I've been trying to solve this problem for a week now and it seems basic, so maybe I'm missing something.
I want to have a div centered on the screen (or its container), and then insert a second div to the right of it, so that afterwards the two of them are centered (space on each side is equal).
Inserting the second div is not a problem, but I need the first block to slide over to where its going to be after the new block is inserted.
http://jsfiddle.net/rdbLbnw1/
.container {
width:100%;
text-align:center;
}
.inside {
border:solid 1px black;
width:100px;
height:100px;
display:inline-block;
}
$(document).ready(function() {
$("#add").click(function() {
$(".container").append("<div class='inside'></div>");
});
});
<div class="container">
<div class="inside"></div>
</div>
<input id="add" type="button" value="add"/>
Do I need to explicitly calculate where the original box is going to end up and then animate that, or is there a better way to do it?

I like your question so decide to write this:
$(document).ready(function() {
var isInAction = false;
var intNumOfBoxes = 1;
var intMargin = 10;
$containerWidth = $(".container").width();
$insideWidth = $(".inside").width();
$(".inside").css('margin-left',($containerWidth - $insideWidth - intMargin)/2 + 'px');
$("#add").click(function() {
if (!isInAction){
isInAction = true;
intNumOfBoxes +=1;
$(".current").removeClass("current");
$(".container").append("<div class='inside current'></div>");
$('.inside').animate({
'margin-left': '-=' + ($insideWidth + intMargin)/2 + 'px'
}, 300, function () {
$(".current").css('margin-left',($containerWidth + ((intNumOfBoxes - 2) * ($insideWidth + intMargin)))/2 + 'px');
$(".current").fadeIn(500,function(){
isInAction = false;
});
});
}
});
});
Also add this class in CSS:
.current {
display:none;
}
You don't need to change variables in JS code except intMargin. you can change this var to set margin between boxes.
Note: This code works fine on older browsers too and not need to support CSS3 features like transition.
Update: Some bugs like repeated clicks fixed.
Check JSFiddle Demo

First, we can animate only things that have explicit numerical values such as width, left or margin. We can't animate things like alignment (which actually use the same margin property but implicitly, never mind). So if we know width of inserted div let's just add it to our container.
1) Let's centre container itself and add transition to it
.container {
width: 102px; /* set explicit width; 102 - because of borders */
margin: auto; /* set margin to 'auto' - that will centre the div */
transition: width 0.5s;
}
2) Then increase the width when add div
$(".container").width($(".container").width() + 102);
3) But wait! If we add div to too narrow container it will be added to bottom not to right. So we need another container set to appropriate width before.
See final example on JSFiddle.
BTW, remove all line breaks and tabs from your code when you use inline-block, because it will cause spaces between your blocks.

Resizing child DIV equal to parent DIV

I have a DIV with width 400px and height 200px. Inside this div is another div with some text at position 50,50 and font-size 14px;
When the parent DIV resizes (for example to 600px x 300px), i want that the text-size inside the child DIV resizes too (to a larger font-size), equal to the resized parent DIV.
How can i do that with jQuery and HTML?

make the child div width and height 100%
childDiv {
display:block;
width: 100%;
height: 100%;
position:relative //so you dont lose the positioning of your text
}

when the parent dives size becomes (600 / 300) from (400 / 200) for example, you should apply a javascript function to the child div like so
function resizeFont(parentElementId, childElementId, newWidth) {
currWidthParentElement = parseFloat( $(parentElementId).width() ); // get current width
currChildFontSize = parseInt( $(childElementId).css('font-size') ); // get font size for child
percentaRaise = (newWidth - ceil(currWidthParentElement)) * (100/ceil(currWidthParentElement)); // calculate how much parent increase
// calculate and apply new font size
newFontSize = currChildFontSize * percentaRaise/100 + currChildFontSize;
$(childElementId).css(newFontSize);
}
is seems tricky but is simple algebra. I hope thihs will help you

http://codepen.io/rafaelcastrocouto/pen/EiFIL
var div = $('div');
$(window).on('resize', function(){
var u = div.width() / 200;
div.css('font-size', u +'em');
});

There is an extension for jquery that allows resize to be fired on elements like it would on the window itself.
The extension: Jquery Resize Plugin
So something like this will do the trick:
$("#parent").resize(function(){
var newFontSize = $("#parent").height() * 0.07
$("#child").css("font-size",newFontSize +"px");
});
Check out this JsFiddle for an example: http://jsfiddle.net/Mm3jr/1/

Scrollpane on the bottom, css is hacky, javascript is hard

I want to put a bar on the bottom of my page containing a varying number of pictures, which (if wider than the page) can be scrolled left and right.
The page width is varying, and I want the pane to be 100% in width.
I was trying to do a trick by letting the middle div overflow and animate it's position with jquery.animate().
Like this:
Here is a fiddle without the js: http://jsfiddle.net/SoonDead/DdPtv/7/
The problems are:
without declaring a large width to the items holder it will not overflow horizontally but vertically. Is this a good hack? (see the width: 9000px in the fiddle)
I only want to scroll the middle pane if it makes sense. For this I need to calculate the width of the overflowing items box (which should be the sum of the items' width inside), and the container of it with the overflow: hidden attribute. (this should be the width of the browser window minus the left and right buttons).
Is there a way to calculate the length of something in js without counting all of it's childrens length manually and sum it up?
Is there a way to get the width of the browser window? Is there a way to get a callback when the window is resized? I need to correct the panes position if the window suddenly widens (and the items are in a position that should not be allowed)
Since the window's width can vary I need to calculate on the fly if I can scroll left or right.
Can you help me with the javascript?
UPDATE: I have a followup question for this one: Scroll a div vertically to a desired position using jQuery Please help me solve that one too.

Use white-space:nowrap on the item container and display:inline or display:inline-block to prevent the items from wrapping and to not need to calculate or set an explicit width.
Edit:: Here's a live working demo: http://jsfiddle.net/vhvzq/2/
HTML
<div class="hscroll">
<ol>
<li>...</li>
<li>...</li>
</ol>
<button class="left"><</button>
<button class="right">></button>
</div>
CSS
.hscroll { white-space:nowrap; position:relative }
.hscroll ol { overflow:hidden; margin:0; padding:0 }
.hscroll li { list-style-type:none; display:inline-block; vertical-align:middle }
.hscroll button { position:absolute; height:100%; top:0; width:2em }
.hscroll .left { left:0 }
.hscroll .right { right:0 }
JavaScript (using jQuery)
$('.hscroll').each(function(){
var $this = $(this);
var scroller = $this.find('ol')[0];
var timer,offset=15;
function scrollLeft(){ scroller.scrollLeft -= offset; }
function scrollRight(){ scroller.scrollLeft += offset; }
function clearTimer(){ clearInterval(timer); }
$this.find('.left').click(scrollLeft).mousedown(function(){
timer = setInterval(scrollLeft,20);
}).mouseup(clearTimer);
$this.find('.right').click(scrollRight).mousedown(function(){
timer = setInterval(scrollRight,20);
}).mouseup(clearTimer);
});

Thanks Phrogz for this part -- give the image container the white-space: nowrap; and display: inline-block;.
You can calculate the width without having to calculate the width of the children every time but you will need to calculate the width of the children once.
//global variables
var currentWidth = 0;
var slideDistance = 0;
var totalSize = 0;
var dispWidth = (winWidth / 2); //this should get you the middle of the page -- see below
var spacing = 6; //padding or margins around the image element
$(Document).Ready(function() {
$("#Gallery li").each(function () {
totalSize = totalSize + parseFloat($(this).children().attr("width"));// my images are wrapped in a list so I parse each li and get it's child
});
totalSpacing = (($("#Gallery li").siblings().length - 1) * spacing); //handles the margins between pictures
currentWidth = (parseFloat($("#Gallery li.pictureSelected").children().attr("width")) + spacing);
maxLeftScroll = (dispWidth - (totalSize + totalSpacing)); //determines how far left you can scroll
});
function NextImage() {
currentWidth = currentWidth + (parseFloat($("#Gallery li.pictureSelected").next().children().attr("width")) + spacing); //gets the current width plus the width of the next image plus spacing.
slideDistance = (dispWidth - currentWidth)
$("#Gallery").animate({ left: slideDistance }, 700);
}
There is a way to get the browser window with in javascript (jQuery example).
and there is a way to catch the resize event.
var winWidth = $(window).width()
if (winWidth == null) {
winWidth = 50;
}
$(window).resize(function () {
var winNewWidth = $(window).width();
if (winWidth != winNewWidth) {
window.clearTimeout(timerID);
timerID = window.setInterval(function () { resizeWindow(false); }, 100);
}
winWidth = winNewWidth;
});
On my gallery there's actually quite a bit more but this should get you pointed in the right direction.

You need to change your #items from
#items
{
float: left;
background: yellow;
width: 9000px;
}
to
#items {
background: yellow;
}
Then calculate the width very easily with jQuery
// #items width is calculated as the number of child .item elements multiplied by their outerWidth (width+padding+border)
$("#items").width(
$(".item").length * $(".item").outerWidth()
);
and simply declare click events for the #left and #right elements
$("#left").click(function() {
$("#middle").animate({
scrollLeft: "-=50px"
}, 'fast');
});
$("#right").click(function() {
$("#middle").animate({
scrollLeft: "+=50px"
}, 'fast');
});
jsFiddle link here
EDIT
I overlooked that detail about the varying image widths. Here is the correct way to calculate the total width
var totalWidth = 0;
$(".item").each(function(index, value) {
totalWidth += $(value).outerWidth();
});
$("#items").width(totalWidth);