Centering a set of divs? - css

I am trying to center this JS/jquery/ajax app screen here, such that no matter what size the user's screen is, it will all remain centered. Right now it is all left-aligned:
http://www.funtrivia.com/html5/indexc.cfm?qid=361927
No matter what I try, it simply does not center. When I do manage to center the outermost div, all of the inner stuff gets messed up.

your html is built wrong. everything seems to be positioned absolute and has a left/top defined. It does not help that your body tag has width: 790px;
This can be solved with just css. Try removing all the positioning styles from the markup and set #game to be margin: 0 auto (the centering trick)

Remove the width settings on your body tag
Use "margin: 0 auto" on your gameheader and game divs
and set your gameheader div and game div to use position:relative

A quick Google Search reveals How to Centre a DIV Block Using CSS
Use the following CSS where #content is the id of your main div element
#content {
margin-left: auto ;
margin-right: auto ;
}
The technique works because when both margins are set to auto, web browsers are required by the CSS standard to give them equal width.
jsFiddle

Related

Strange container div behaviour

I'm asking this for learning purposes; there aren't any negative aspects on this behaviour, but I just wonder if this could have any negative consequences in the future.
So I have a container div: content_wrap, which has two other div's: side_bar and main_content. The container div is 980px width, and is used to center its contents using margin-left and margin-right.
It's doing this correctly, however, when I was debugging the page (in Firefox), I noticed that the browser renders the div as being 0x0px and renders the parent div off-screen. However, it does position the child divs correctly. See this JSFiddle for an example: http://jsfiddle.net/7fsXp/7/
I Googled this and most of the answers have something to do with floats and are solved by using clear:both, but I don't use any floats. I did notice that if I change the main_content div from position:absolute; to position:relative;, the content_wrap is displayed correctly. Or I can fix it by setting a height for content_wrap.
I don't actually need to be able to see the content_wrap, so there isn't really a problem, as it is doing its job in means of centering the child divs. I just wondered if it would be a bad practice to leave it like this? Is it a bad thing, or does it matter?
Try adding other elements to this HTML and enjoy the horror :D
There are actually many things in your code, that I wouldn't do. First of all, when an element is with position: absolute or position: fixed its layout is "ignored" by other elements or in other words cannot "push" any element and that is why your container is having 0 height. It's like they are ethereal (best explanation ever, I know).
You should check this article on positioning -- http://css-tricks.com/absolute-relative-fixed-positioining-how-do-they-differ/
The fact that they are in the place you expect them to be is that there are actually no other elements in the HTML and the absolute element is positioned relatively to the body and so is the fixed one (but that's what elements with position: fixed always do). Looks what happens when I add some other content to the parent div -- http://jsfiddle.net/7fsXp/13/
So long story short - you shouldn't form your layout with absolute or fixed elements if you can do it without them.
position: fixed and position: absolute take the elements out of the flow, so using either of these positions on all child divs will collapse the parent div entirely.
If you have content below a collapsed div, it will flow up and over/under that content like this.
You don't need to position the main_content div absolutely, but you'll need to change a few things to top align the sidebar and main_content.
DEMO
Since sidebar is fixed, it's using the document, not the container div as a reference for top, while main_content would use the body (unless you add position: relative to the container). Getting rid of the body's default padding/margin will fix the small alignment difference.
body {
padding: 0;
margin: 0;
}
#main_content {
//remove position: absolute;
margin-top:70px; //top: 70px won't work unless you specify position
}
It depends on what you are willing to do, but because the default position for div is position: static; changing the position: relative; will avoid the collapse of parent div.

Possible to achieve affect of overflow hidden without actually hiding the overflow?

I have an image slider which is positioned absolute and has a width of 1280px. The margin-left is -160px to center it in its parent. The parent width is 960px with margin set to '0 auto' to achieve a centered affect.
The image slider should only take up width:960px so that the overflow doesn't cause the browser to handle it with scrollers. Is it possible to achieve something like overflow:hidden while still showing the overflow content at high screen resolutions?
problem example: http://almightyidea.com/test/slider/
basic css:
.slide-wrapper {
position:relative;
width:960px;
margin:0 auto;
}
.slideshow{
position:absolute !important;
margin-left:-160px;
}
I think you should use relative widths for the wrapper. So let it expand wider when the is room to do so. You could also use JavaScript to calculate the width of the viweport for you and set that width to the wrapper.
You could also just use an existing jQuery plugin to do all the heavy lifting. I use Cycle when I need to do stuff like this. http://jquery.malsup.com/cycle/

How can I make a div assume 100% of its containing div?

I'm trying to make a div assume 100% of it's parent div. The parent div acts as a page wrapper, so it's already assuming 100% of the page width. I've tried adding width: 100%, but this did not seem to work. I'm a little baffled, because this seems like a relatively simply thing to do.
Don't specify a width at all. For a div element (or any block level element for that matter), this will make it assume 100% width regardless what padding/margin settings it has set.
Depending on the box model, explicitly setting 100% width can actually make the element too wide because paddings are calculated into it.
If this doesn't work, there is some other CSS setting interfering and you need to show more of your layout and HTML code.
display: block;
width: auto;
Should work for you.
You need to show more of your existing css code as normally, a div takes by default the whole space available to it, provided it has some content.
Other than that, make sure you set margin and padding of the parent div to 0.
.parent{
margin:0;
padding:0;
overflow:auto;
}
.child{
margin:0;
padding:0;
}

Background image is longer than the enclosing div

On a customer website, I have to add a background image for only a contained region of the page (its real content part).
The problem is, if the content is short enough, then the image will be clipped. How would be possible to have the image completely visible? I have tried to add the "overflow" CSS attribute but unfortunately it did not help me.
Here is an example of the website I have to work on: http://www.sfp-pensioen.nl/werknemer/welkom The background image is on the div element with id="content".
On the specific link that I am sending it is not an issue because the content is long enough, but if you remove elements using firebug then the problem will become obvious.
ps: IE6 must be supported.
Following on from Graham's answer:
"height" in ie6 acts like "min-height" across other browsers.
min-height: 50px;
_height: 50px;
The example above will provide a cross browser minimum height of 50px. ie6 will read "_height" where other browsers will not. If you don't hacks, use a conditional statement.
Rich
you could either give a height to the id #content
or
apply the background:url("/images/Doelgroep-Background-Image.jpg") no-repeat scroll left top transparent; to #mainContent instead of #content
overflow for background-images is impossible, but you could set a min-height for content (or set the image in another div with lower z-index and position it abolutely to appear at the place you want - but thats a very bad solution)
The overflow attribute controls what happens to the div when the content is too big to fit - if you have a fixed-size div with some content that might overflow, you generally want the auto option. overflow has no effect on a background image.
For your case, it sounds like you want to specify a min-height on the content div. Note that this isn't supported by older browsers like IE6, which you may or may not care about. There are plenty of ways to work around this, though.
What you want is the 100% height you can achieve this with the following.
html {
height: 100%;
}
body {
height: 100%;
}
#content {
height: 100%;
}
You need the min-height and the body needs a height so every child element of the body will follow the rule.
Also by adding min-height: 100%; to all css rules will solve all your problems for any grade A browser.
If you know the #sidebar or #main will always have a visual height the same or larger than the background image then you can simply add the background image to:
.sub #wrapper #mainContent {
background:url("/images/Doelgroep-Background-Image.jpg") no-repeat scroll 0 150px transparent;
}
instead of where it is an the moment on #content

Seeking CSS Browser compatibility information for setting width using left and right

Here's a question that's been haunting me for a year now. The root question is how do I set the size of an element relative to its parent so that it is inset by N pixels from every edge? Setting the width would be nice, but you don't know the width of the parent, and you want the elements to resize with the window. (You don't want to use percents because you need a specific number of pixels.)
Edit
I also need to prevent the content (or lack of content) from stretching or shrinking both elements. First answer I got was to use padding on the parent, which would work great. I want the parent to be exactly 25% wide, and exactly the same height as the browser client area, without the child being able to push it and get a scroll bar.
/Edit
I tried solving this problem using {top:Npx;left:Npx;bottom:Npx;right:Npx;} but it only works in certain browsers.
I could potentially write some javascript with jquery to fix all elements with every page resize, but I'm not real happy with that solution. (What if I want the top offset by 10px but the bottom only 5px? It gets complicated.)
What I'd like to know is either how to solve this in a cross-browser way, or some list of browsers which allow the easy CSS solution. Maybe someone out there has a trick that makes this easy.
The The CSS Box model might provide insight for you, but my guess is that you're not going to achieve pixel-perfect layout with CSS alone.
If I understand correctly, you want the parent to be 25% wide and exactly the height of the browser display area. Then you want the child to be 25% - 2n pixels wide and 100%-2n pixels in height with n pixels surrounding the child. No current CSS specification includes support these types of calculations (although IE5, IE6, and IE7 have non-standard support for CSS expressions and IE8 is dropping support for CSS expressions in IE8-standards mode).
You can force the parent to 100% of the browser area and 25% wide, but you cannot stretch the child's height to pixel perfection with this...
<style type="text/css">
html { height: 100%; }
body { font: normal 11px verdana; height: 100%; }
#one { background-color:gray; float:left; height:100%; padding:5px; width:25%; }
#two { height: 100%; background-color:pink;}
</style>
</head>
<body>
<div id="one">
<div id="two">
<p>content ... content ... content</p>
</div>
</div>
...but a horizontal scrollbar will appear. Also, if the content is squeezed, the parent background will not extend past 100%. This is perhaps the padding example you presented in the question itself.
You can achieve the illusion that you're seeking through images and additional divs, but CSS alone, I don't believe, can achieve pixel perfection with that height requirement in place.
If you are only concerned with horizontal spacing, then you can make all child block elements within a parent block element "inset" by a certain amount by giving the parent element padding. You can make a single child block element within a parent block element "inset" by giving the element margins. If you use the latter approach, you may need to set a border or slight padding on the parent element to prevent margin collapsing.
If you are concerned with vertical spacing as well, then you need to use positioning. The parent element needs to be positioned; if you don't want to move it anywhere, then use position: relative and don't bother setting top or left; it will remain where it is. Then you use absolute positioning on the child element, and set top, right, bottom and left relative to the edges of the parent element.
For example:
#outer {
width: 10em;
height: 10em;
background: red;
position: relative;
}
#inner {
background: white;
position: absolute;
top: 1em;
left: 1em;
right: 1em;
bottom: 1em;
}
If you want to avoid content from expanding the width of an element, then you should use the overflow property, for example, overflow: auto.
Simply apply some padding to the parent element, and no width on the child element. Assuming they're both display:block, that should work fine.
Or go the other way around: set the margin of the child-element.
Floatutorial is a great resource for stuff like this.
Try this:
.parent {padding:Npx; display:block;}
.child {width:100%; display:block;}
It should have an Npx space on all sides, stretching to fill the parent element.
EDIT:
Of course, on the parent, you could also use
{padding-top:Mpx; padding-bottom:Npx; padding-right:Xpx; padding-left:Ypx;}

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