This is the scenario.
I have a simple table with a header row including several columns which have a dynamically changing width. Within the head row there are lists of a height that is longer than the head rows height, they are however only supposed to be visible on hover, but when on hover they are supposed to be ontop of the headrow but still having the the original 100% width of the parent being the <td> element of the column.
What I did was to set position: absolute on hover but as soon as that happens the element obviously took all the width it can get, fixable only with a specificly applied width, but that doesn't really help me as the column can be resized.
My Question is if there is a way in CSS ( NOT Javascript ) to achieve a behaviour where the element would still use the parent's width.
The answer to your question will vary wildly depending on what you're trying to accomplish. Most blanket solutions require:
The addition of extra positioning elements (often added using Javascript)
Setting display: block; on the TH, TD elements (often makes the TABLE behave erratically)
The reasons for this is that adding positioning to a table cell removes it from the flow, which affects table alignment (see this bug report comment). A much longer discussion about this issue and the possible solutions can be found at Does Firefox support position: relative on table elements?
That aside…
If you are using the TABLE for site layout, stop now and re-think your choices in life. There are better options:
The best option will be the CSS3 Flexible Box Layout model, if and when it becomes widely supported. Support at the time of this writing is minimal, scattered, and doesn't always follow the same standard (caniuse.com: flexbox)
Until that becomes an option, it's a little known fact that absolutely positioned elements can be positioned inside absolutely positioned elements. See this fiddle for an example of a 100% width/height layout made possible with absolutely positioned elements. Alternatively, the same layout can be made inside a relatively positioned parent element.
If you're not using a TABLE for site layout, then there may be other options open to you. It depends on the desired effect.
Related
I've been working with HTML and CSS for a while now.
Every time I work in CSS, I have a feeling that I'm not "doing it right".
For instance, when positioning different divs and elements on a webpage, I use "position: absolute" and "position: relative" quite often.
This can sometimes be very tedious to find the "right" position and results in very ugly numbers, such as:
position: relative;
width: 1300px;
height: -720px;
In addition to above, it also makes it very difficult to edit said divs and elements later on if I change my mind about their appearance or position.
I've watched a lot of tutorials on YouTube where people use "margin" and "padding" tags to position the elements on their websites.
I'm very confused by this since those tags are supposed to be used for creating space around elements and not actually change their position.
The strange thing is, that it is much easier to edit the website using "margin" and "padding" tags later on, if you change your mind about the appearance/positioning of those elements since they won't move around and overlap each other.
I apologize for the long query but this has been bothering me a lot lately and I would appreciate any advice regarding the positioning of elements in CSS.
Thank you
The biggest distinction between position and margin or padding is that when you set the position to absolute, relative or fixed, the element is taken out of the "normal flow" of the document and placed in its own layer. This is what allows you to use the z-index property and stack elements on top of each other. This has dramatic advantages when the elements in question are going to be dynamically sized or animated because doing so won't cause all other elements in the document to have to "re-flow", nor will the entire document have to "re-paint". In fact, when working with dynamic sizing or animations it is strongly recommended that you take elements out of the flow this way or performance can suffer.
Beyond this, understanding how absolute, relative and fixed positioning work is essential.
Absolute Positioning positions the element relative to its nearest ancestor that, itself, has been manually positioned or the body element if no ancestor has been positioned. The element is taken out of the flow and any space the element was taking up in that flow is removed.
Relative Positioning positions the element as an offset to its original location in the normal flow, but leaves the original space that the element took up in the document even though the element is now in its own layer.
Fixed Positioning is similar to absolute, except that the position is not relative to anything. It is fixed at an exact location you specify.
While all of these will pull the element into its own layer, how the layers are stacked (via "stacking contexts") are dependent upon which type of positioning you've used and the structure of the elements being positioned.
These are the reasons to use position. If you are not in need of new layers, using CSS float, flexbox are tools that can offer alternative ways to design a layout.
margin and padding should really not be used for the layout itself. They are used for small tweaks within a layout.
In summary, the default way the a browser lays out the contents of a page is the CSS Box Model, but using CSS position is one way to have certain content use that box model in different layers from the main content. CSS floats offer another, separate layout algorithm and Flexbox offers yet another. In the near future, the CSS Grid specification will be standardized and yet another layout paradigm will be available.
But margin and padding are not layout models. They are just tools to use in whatever layout model you happen to be using.
I've always wondered about this.
Even with media queries, how would I significantly change the placement of things(since I'm not modifying element placement in HTML directly).
For example, if social Facebook/Twitter links appear somewhere in the middle of the page(with their HTML container elements nested in a bunch of other parent tags), how would I go about moving that to the bottom of the page(or, to make it look like they are nested in a different section).
You have at least two options:
Change the positioning of the container element. Instead of static position (default behavior), you can use position: absolute or position: fixed to move it to a totally different place on your page.
Repeat the elements in two different places, and set one of them visible depending on a screen size.
I must add, however, that in a good design such measures are rarely necessary. You do not want to confuse your users by moving the elements to a totally different location. A better approach is to use a responsive grid (for example, changing the layout from three columns to two, or from two to one, when a screen gets smaller), collapse tabs into a drop-down list, etc., but keep the position of different elements relatively stable.
Moving to the bottom of the page wouldn't be a big deal. Depending on the parent container, use position:absolute or position:fixed and adjust the z-index of this and the parent container.
However, if you wanted to re-order your containers for specific media queries, you'll either have to give absolute positioning to more elements, adjust your floats, or use Javascript.
If this is a client request, I would personally revisit the wireframe stage and plan your responsive behavior from scratch.
You never ever can assume height of elements for sure from a CSS perspective: user will zoom a bit or a lot, images included or not; images won't appear because of network problem or by user choice, etc. Thus position: absolute is a recipe for future or immediate failure (and fixed not what you're searching for).
You can play with:
flexbox (horizontal or vertical, natural or reverse order)
display: table-(header|footer)-group or display: table-caption along with table-cell and if possible with parent element having display: table (with or without table-layout: fixed) or table-row
floats and Block Formatting Context effects (such a powerful beast)
nope: CSS Grid Layout is IE10 and IE11 only
If you want to move an element from somewhere inside some other element far away both in HTML and visually, then go with JS/jQuery. CSS doesn't allow for complex manipulations. Just make sure that you watch for resize both from and to desktop/mobile resolutions (and allow for initial manipulation and after some AJAX event) and don't fire 100+ events per second when resizing
I'm trying to get more efficient with building responsive websites and since I'm using Bootstrap (not particularly important for this case - I believe), I was looking into Bootsnipp. I decided to view the site's source and noticed one thing I've never seen before: they did not set a height for any of their containers except for the whole page wrapper and the footer. This baffles me because everything falls into place with the website and it's super repsonsive. I understand the elements where they use Bootstrap's classes like "col-sm-4" and whatnot but does anyone understand the art of making the header, a content container, etc calculate heights without specifying in css? Can anyone explain this concept? I tried Googling but not sure of the correct keywords to find answers.
Also, if you need to see yourself, here is the link to their CSS.
Thanks
Understanding the Box Model is important. As an (overly simplified) rule of thumb, you can think of it like this; there are 2 primary types of elements: inline (span, b, strong, ...) and block (div, p, ...).
Block tags by default are width: 100%. That is to say they will naturally stretch to fill their horizontal area.
Inline tags you can think of as being constricting. They shrik to fit the size of their inner elements. This makes sense when you think of a bold tag: it is not unlike highlighting the text you want to be bold. It stays small to fit the content.
In both cases, though, unless you specify a height, both block and inline tags will shrink their height to fit their inner elements. Because of this, you can think of a website as being a bunch of elements stacked on top of each other, where the top of the page is the bottom of the "stack".
Here is an example of divs without specified heights having their heights changed by the size of the interior content. http://jsfiddle.net/S3q2C/ Notice all the divs have a border to easily see its relative size.
If you don't set an explicit height, containers will automatically grow to fit the content (respectively). Sometimes this is desirable, other times not (think overflow hidden). A possible reason why people use explicit heights in containers could be because of absolute positioning, or if they want to align a nested element that is 50px tall, with another that is 200px tall. An explicit height could also be used to maintain perspective say for a picture or other element (maybe a series of elements). While this answer is the end all be all you might be looking for, the key thing I'm trying to pass along is that an explicit height is used when needed, not all the time.
Here's a quick demo showing you two <div> containers, one with a height set, and another with no height.
http://jsfiddle.net/xrZ73/1/
I am currently working on a prototype that is using CSS3 multi columns for dividing up content and it appears to work well. My issue is that inside of a block that is part of the columns there is an expanding height section and well, in Firefox when the height of an element inside of a CSS3 multi-column changes it disappears and then Firefox crashes.
Shouldn't CSS3 multi-columns take into account varied height content inside or is it not made for that sort of thing? I'd really hate to have to use a plugin like Columnizer, because Columnizer is a pain in the butt to get working correctly.
Here is the layout:
[DIV]
[CONTENT] - Default height is 38 pixels
[EXPAND LINK] - A link when clicked that modifies the height of content to be 52 pixels.
[/DIV]
The issue is as soon as the link is clicked and the height changes, it's like it loses its layout and positioning (the height and width change to 0), then Firefox crashes. This is also the case if I use Firebug to change the height manually.
I resolved the issue right are posting this question basically and my solution was as follows in-case someone else runs into this issue which I believe some will.
I had a parent div element with the appropriate CSS3 multi-column code. The inner elements are article elements (you could just use div's though). The issue was that the inner article elements were being floated left (just out of pure habit of having to float things to give the appearance of columnised items). The floated elements were clashing with the CSS3 multi-column code thus crashing the browser.
I'm guessing that because a float modifies the layout of an element, the multi-column code was trying to perhaps readjust the box and then getting into an endless loop. I'm not entirely sure what went on, but floating elements inside of a multi-column div or anything is bad.
I'm learning HTML and I wanted to practice by recreating a invoice sent to me by Electronics Expo.
However, I used the background-image property and repeated it by repeat-x and now, the background stretches across the page so much that it has a horizontal bar to drag.
http://htmlpocketreference.110mb.com/index.html
You can see what I did in my link above.
Also, I would really appreciate some advice on simplifying my CSS coding. It seems really messy and I have to move every element once something changes. -.-
Thanks!
It's because you have relatively positioned elements that do not have a fixed width - these elements take on the width of their parents, which is the width of your invoice, and stick out of the page, causing the overflow. Give them a background color, and you can see this quite clearly:
Give the elements a fixed width to fix this, or alternatively, look to other methods of laying out your elements, like floating them.
In addition to this problem, you're also repeating the id attribute, which is creating invalid HTML. You should look at using the class attribute for multiple elements sharing the same style, or even better, look at using inheritance and the cascade to not have to give every single element an id.
Further reading:
CSS Positioning 101
Inheritance and Cascade from The Web Standards Curriculum
Problem is not the background. The problem is the position relative you're giving to the block level elements without defining their width...
The h2 elements like (Ship To:) and (Phone) and all the paragraph elements. You need to give these elements a specific width and it will work fine
Try giving these elements a background-color: yellow; to see how the flow inside the document ( for your debugging purpose ) and you will see what I mean