I'm trying to get a site I'm working on to be WCAG 2 compliant. The site uses image sprites and it would be a challenge to replace the usage of image sprites throughout. As such I'm trying to determine whether the following technique:
<div style="background: url(flower.png); height: 20px; width:20px;">
<div style="text-indent: 100%; white-space: wrap; overflow: hidden">
A red rose
</div>
</div>
Is sufficiently compliant. From reading the documentation... it's unclear.
For a non-decorative img tag use of alt is definitely a requirement: H37: Using alt attributes on img elements
And for a media objects, wrapping content is sufficient: H53: Body of Object
But whether using the body of a a div that has a non-decorative image background passes muster isn't very clear.
Can anyone speak to this or point me to the relevant page in the standard?
There are a couple of scenarios this could be, the advice will change depending on whether it is:
Content images (e.g. a gallery)
Functional elements like a navigation or toolbar options.
If they are content images (which 'red rose' implies), then I think this technique applies:
http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-TECHS/C30.html
In which case your approach would meet WCAG if people could display it without the image in order to read the alt-text. That might sound odd, but assistive technologies have long known how to read alt attributes, but image-replacement can be done in many ways and they may not be able to tell when it is used.
Screen reader users would probably find it ok, but other groups who need alt-text probably wouldn't be able to read the text in a 20x20px box. For example, if you turn on high-contrast mode in Windows, background CSS images are dropped and the text would not be visible.
If they are functional elements and the image is an icon, e.g. a "save" button, then you want a visible (e.g. tooltip) and programatic label, in which case I would suggest:
<div style="background: url(flower.png); height: 20px; width:20px;"
role="button" aria-label="Save" title="Save" tabindex="0"></div>
However, you would be better off using foreground images or font-icons, as these are far more robust in different situations. For example, if you included a font-icon you could use:
<button>
<span class=”icon-save” aria-hidden="true"></span>
<span class=”alt”>Save</span>
</button>
With something like this as the CSS, assuming you have already imported the correct font to use:
.icon-save:before {
font-family: icons;
content: ⇝ /* whatever your icon reference is */
}
.alt {
position: absolute;
left: -9999px;}
How can I show an image as a tool tip in my web page. I want my tool tip in a custom image, rather than the usual one. I tried defining a class to hold the image and added the class to the anchor element, but I did not get the image. Someone help me.
My css:
.bubbleText{
background:transparent url(../images/static/link_hover_M_120.png) no-repeat;
}
.questionIcon{
background: url(../images/static/question2.png) no-repeat;
text-decoration:none;
}
My html code:
<a title="Your Contact number" href="#" class="questionIcon bubbleText"> </a>
The questionIcon class hold a 'question mark' image. On hovering on the question mark, I need the tool tip to be displayed inside the image. The image is just a white box with borders.
If you mean you want to style the tooltip you'll need to use javascript to create the functionality. What script you use depends on what JS framework you're using, if any.
There's a big list of tooltips on this site : http://www.1stwebdesigner.com/css/stylish-jquery-tooltip-plugins-webdesign/
Uses different frameworks, so pick the one that works for you.
I would use a common library like jQuery. There are a lot of running examples: http://jquery.bassistance.de/tooltip/demo/
Browsers don't support rich tooltips but it can still be done
The easiest way is to use some plugin (if you're using something like jQuery) that provides rich tooltips functionality. Browsers can only display text that's defined in alt attribute (of image elemnt) or title attribute in any other HTML element (including image).
This will get you started on jQuery tooltip plugins.
I am designing my first website.
I have designed a button image in gimp and saved it as a jpg.
I want to use this button for my navigation buttons on the site. Should I make a separate image(jpeg) for each button or is it possible to just use one image and then overlay text on top of the images on the page using HTML? What's the best practice here?
Usually in this case you use just CSS by setting background property of elements that should be your navigation buttons.
For example you could have a ul:
<ul>
<li>Button1</li>
<li>Button2</li>
<li>Button3</li>
</ul>
and then just style it in you css by using background-image or similar styles, take a look here for some examples..
You're asking a question more about design than about coding. If you can implement your desired design by developing a single button background and then overlaying text in a standard font, do it! More broadly: don't put text in an image if you're just using a standard font.
On the other hand, if you want a fancy swirly font that can only be depicted in an image, you'll need to create a specialized image for each button with that button's text.
In that case, be sure to insert the image purely with CSS. Never, ever embed an <img /> tag with a textual button on a page.
Definitely reuse the images and overlay text. For ideas on how to do this, look at this tutorial:
Image button overlay text tutorial
Also, you mentioned using jpg. Consider using PNG instead for the button images, unless they are "real world" images. For simple gradients and solid colors, PNG is the way to go.
I havent seen the image but I generally try to Use CSS for as much of the graphical design as possible. Button generally tend to be very simple in design. However if you must use an image you can assign a background to a tag and then use text in the tag. Example would be to assign a background to a
<button class="myButtonClass">MyButtonText</button>
<style>
.myButtonClass {
//enter your button style here.
}
</style>
Depends on how you've designed you site, as always theres loads of ways to do everything.
If your buttons are just static i would recommend using images, theres no harm doing it like this.
<span>Your button</span>
then you can use the css to set the image background.
.home{display:block; height:20px; width:40px; background:url(image.gif);}
and your also gonna need to hide the text in the span.
.home span{display:none;}
Theres no harm in using simple text either, most of the time its personal preference.
Just leave ou the .home span{display:none;} and replace it with something to centre the text in the button.
As mentioned in another answer its also good practice to wrap your images in list items. Might sound wierd at first. But in practice its the best way.
you can put the image as backgroud...
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In what situations is it more appropriate to use an HTML IMG tag to display an image, as opposed to a CSS background-image, and vice-versa?
Factors may include accessibility, browser support, dynamic content, or any kind of technical limits or usability principles.
Proper uses of IMG
Use IMG if you intend to have
people print your page and you want the image to be included by default.
—JayTee
Use IMG (with alt text) when the image has an important semantic meaning, such as a warning icon. This ensures that the meaning of the image can be communicated in all user-agents, including screen readers.
Pragmatic uses of IMG
Use IMG plus alt attribute if the image
is part of the content such as a logo or diagram or person (real person, not stock photo people).
—sanchothefat
Use IMG if you rely on browser scaling to render an image in proportion to text size.
Use IMG
for multiple overlay images in IE6.
Use IMG with a z-index in order
to stretch a background image to fill its entire window.Note, this is no longer true with CSS3 background-size; see #6 below.
Using img instead of background-image can dramatically improve performance of animations over a background.
When to use CSS background-image
Use CSS background images if the
image is not part of the content.
—sanchothefat
Use CSS background images when
doing image-replacement of text eg. paragraphs/headers.
—sanchothefat
Use background-image if you intend to have
people print your page and you do not want the image to be included by default.
—JayTee
Use background-image if you need to improve download times, as
with CSS sprites.
Use background-image if you need for only a portion of the image to be visible, as with CSS sprites.
Use background-image with background-size:cover in order to stretch a background image to fill its entire window.
It's a black and white decision to me. If the image is part of the content such as a logo or diagram or person (real person, not stock photo people) then use the <img /> tag plus alt attribute. For everything else there's CSS background images.
The other time to use CSS background images is when doing image-replacement of text eg. paragraphs/headers.
I'm surprised no one's mentioned this yet: CSS transitions.
You can natively transition a div's background image:
#some_div {
background-image:url(image_1.jpg);
-webkit-transition:background-image 0.5s;
/* Other vendor-prefixed transition properties */
transition:background-image 0.5s;
}
#some_div:hover {
background-image:url(image_2.jpg);
}
This saves any kind of JavaScript or jQuery animation to fade an <img/>'s src.
More information about transitions on MDN.
Above answers considers only Design aspect . I am listing it in SEO aspects.
When to use <img />
When Your Image need to be indexed by search engine
If it has relation to content, including cards (click areas), but not related to design. Design is probably the most difficult thing to parse here because so it's all design right. I would say perhaps functional design (Cards, thumbnails, profile images, things you can click) vs Aesthetic design which is mostly used for sites appeal.
List item
If your image is not too small ( not iconic images ).
Images where you can add alt and title attribute.
Images from a webpage which you want to print using print media css
When to use CSS background-image
Images Purely Used to Design.
No Relation With Content.
Small Images which we can play with CSS3.
Repeating Images ( In blog author icon , date icon will be repeated for each article etc.,).
As i will use them based on these reasons. These are Good practices of Search Engine Optimization of Images.
Browsers aren't always set to print background images by default; if you intend to have people print your page :)
If you have your CSS in an external file, then it's often convenient to display an image that's used frequently across the site (such as a header image) as a background image, because then you have the flexibility to change the image later.
For example, say you have the following HTML:
<div id="headerImage"></div>
...and CSS:
#headerImage {
width: 200px;
height: 100px;
background: url(Images/headerImage.png) no-repeat;
}
A few days later, you change the location of the image. All you have to do is update the CSS:
#headerImage {
width: 200px;
height: 100px;
background: url(../resources/images/headerImage.png) no-repeat;
}
Otherwise, you'd have to update the src attribute of the appropriate <img> tag in every HTML file (assuming you're not using a server-side scripting language or CMS to automate the process).
Also background images are useful if you don't want the user to be able to save the image (although I haven't ever needed to do this).
About the same as sanchothefat's answer, but from a different aspect. I always ask myself: if I would completely remove the stylesheets from the website, do the remaining elements only belong to the content? If so, I did my job well.
Some answers overcomplicate the scenario here. This is a dead simple situation.
Just answer to this question every time you'd like to place an image:
Is this part of the content or part of the design?
If you can't answer this, you probably don't know what you're doing or what you want to do!
Also, DO NOT consider beside the two technique, just because you'd wish to be "printer friendly" or not. Also DO NOT hide content from a SEO point of view with CSS. If you find yourself managing your content in CSS files, you shot yourself in the leg. This is just a trivial decision of what is content or not. Every other aspect should be ignored.
I would add another two arguments:
An img tag is good if you need to resize the image. E.g. if the original image is 100px by 100 px, and you want it to be 80px by 80px, you can set the CSS width and height of the img tag. I don't know of any good way to do this using background-image. EDIT: This can now also be done with a background-image, using the background-size CSS3 attribute.
Using background-image is good when you need to dynamically switch between sprites. E.g. if you have a button image, and you want a separate image displayed when the cursor is hovering over the element, you can use a background image containing both the normal and hover sprites, and dynamically change the background-position.
One more benefit from using the <IMG> tag is related to SEO - i.e. you can provide additional information about the image in the ALT attribute of the image tag, while there's no way to provide such information when specifying the image through CSS and in that case only the image file name may be indexed by search engines. The ALT attribute definitely gives the <IMG> tag SEO advantage over the CSS approach. That's why according to me it is better to specify the images you want to rank well in the image search results (e.g. Google Image Search) using the <IMG> tag.
Foreground = img.
Background = CSS background.
Use background images only when necessary e.g. containers with image that tiles.
One of the major PROS by using IMAGES is that it is better for SEO.
Using a background image, you need to absolutely specify the dimensions. This can be a significant problem if you don't actually know them in advance or cannot determine them.
A big problem with <img /> is overlays. What if I want an CSS inner shadow on my image (box-shadow:inset 0 0 5px rgb(0,0,0,.5))? In this case, since <img /> can't have child elements, you need to use positioning and add empty elements which equates to useless markup.
In conclusion, it's quite situational.
A couple of other scenarios where background-image should be used:
When you want the image to change when the mouse is hovered upon it.
When you want to add rounded corners to the image. If you use img, the image leaks out of the rounded corners.
Use CSS background-image in a case of multiple skins or versions of design. Javascript can be used to dynamically change a class of an element, which will force it to render a different image. With an IMG tag, it may be more tricky.
Here's a technical consideration: will the image be generated dynamically? It tends to be a lot easier to generate the <img> tag in HTML than to try to dynamically edit a CSS property.
What about the size of the image? If I use the img tag, the browser scales the image. If I use css background, the browser just cuts a chunk from the larger image.
img is an html tag for a reason, therefore it should be used. For referencing or to illustrate things, people e.g: in articles.
Also if the image has a meaning or has to be clickable an img is better than a css background. For all other situation, I think, a css background can be used.
Although, it is a subject that needs to be discussed over and over.
Web Student from Paris, France
In regards to animating images using CSS TranslateX/Y (The proper way to animate html) - If you do a Chrome Timeline recording of CSS background-images being animated vs IMG tags being animated you will see the paint times are drastically shorter for the CSS background-images.
There's another reason! If you have a responsive design and want to split usage of low, medium, and high-res images for devices through media queries, you should use backgrounds as well.
Also, i have a gallery section which has inconsistent picture sizes so even though those images are obviously considered content, I use background images and center them in divs with a set size. This is similar to what facebook does in their albums..
Just a small one to add, you should use the img tag if you want users to be able to 'right click' and 'save-image'/'save-picture', so if you intend to provide the image as a resource for others.
Using background image will (as far as I'm aware on most browsers) disable the option to save the image directly.
A small input,
I have had problems with responsive images slowing down the rendering on iphone for up to a minute, even with small images:
<!-- Was super slow -->
<div class="stuff">
<img src=".." width="100%" />
</div>
But when switching to using background images the problem went away, this is only viable if targeting newer browsers.
HTML is for content and CSS is for design. Is the image necessary and does it need to be picked up by screen readers? If the answer is yes, then put the image in the HTML. If it is purely for styling, then you can use the background-image property in CSS to inject the image. Just as a lot of people here have already mentioned, you can then use a pseudo element on the image if you like.
IMG load first because the src is in the html file itself whereas in the case of background-image the source is mentioned in stylesheet so the image loads after the stylesheet loaded, delaying the loading of the webpage.
Another background-image PRO: Background-images for <ul>/<ol> lists.
Use background images if they are part of the overall-design and are repeated on multiple pages. Preferably in background sprite form for optimization.
Use tags for all images that are not part of the overall design, and are most likely placed once, like specific images for articles, people, and important images that deserve to be added to google images.
** The only repeated image that I enclose in a <img> tag is the site/company logo. Because people tend to click it to go to the homepage, thus you wrap it with an <a> tag.
Also note that most search engine spiders don't index CSS background images therefore the background images will be ignored and you won't be able to get any traffic from search engines (no SEO benefit in short).
Where as all images defined with tags are indexed (unless manually excluded) and can bring in traffic from search engines if their title/alt attributes and filenames are optimized properly (w.r.t some keyword).
You can use IMG tags if you want the images to be fluid and scale to different screen sizes. For me these images are mostly part of the content. For most elements that are not part of the content, I use CSS sprites to keep the download size minimal unless I really want to animate icons etc.
I use image instead of background-image when i want to make them 100% stretchable which supported in most browsers.
If you want to add an image only for the special content on the page or for only one page the you should use IMG tag and if you want to put image on more than one pages then you should use CSS Background Image.
I generally use a manual process:
Look at the page, figure out the semantic elements, and build the HTML
Slice up the images I think I'll need
Start writing CSS
Tweak and repeat different steps as necessary
Got a better approach, or a tool?
I have a fairly natural way of coding. The key is to treat the page like a document or an article. If you think of it like this the following becomes logically clear:
The page title is a top level heading
Whether you make the site title or actual page title the h1 is up to you - personally I'd make About Us the h1 rather than Stack Overflow.
The navigation is a table of contents, and thus an ordered list - you may as well use an ol over a ul.
Section headers are h2, sections within those sections are h3s etc. Stack them up.
Use blockquotes and quotes where possible. Don't just surround it with ".
Don't use b and i. Use strong and em. This is because HTML is structural rather than presentational markup. Strong and emphasis tags should be used where you'd put emphasis on the word.
<label> your form elements.
Use <acronym>s and <abbr>s where possible, but only in the first instance.
The easiest: always, always give your images some alternate text.
There's lots of HTML tags you could use that you probably haven't - address for postal addresses, screen code output. Have a look at HTML Dog for some, it's my favourite reference.
That's just a few pointers, I'm sure I could think of more.
Oh, and if you want a challenge write your XHTML first, then write the CSS. When CSS-ing you aren't allowed to touch the HTML. It's actually harder than you think (but I've found it's made me quicker).
Well, when I build a website I tend to try and forget about the design completely while writing the HTML. I do this so I won't end up with any design-specific markup and so I can focus on the semantic meaning of the elements.
Some pointers how to markup things:
menu - use the UL (unordered list) element, since that's exactly what a menu is. an unordered list of choices. example:
<ul id="menu">
<li id="home">Home</li>
<li id="about">About</li>
</ul>
if you'd like an horizontal menu you could do this:
#menu li {
display: block;
float: left;
}
Logo - use a H1 (heading) element for the logo instead of an image.Example:
<div id="header">
<h1>My website</h1>
</div>
And the CSS (same technique can be applied to the menu above if you would like a menu with graphical items):
#header h1 {
display: block;
text-indent: -9999em;
width: 200px;
height: 100px;
background: transparent url(images/logo.png) no-repeat;
}
IDs and classes - use IDs to identify elements that you only have one instance of. Use class for identifying elements that you got several instances of.
Use a textual browser (for instance, lynx). If it makes sense to navigate in this way, you've done good when it comes to accessibility.
I hope this helps :)
I essentially do the same thing Jon does, but here are a few other ideas:
Use Guides in Photoshop (and lock to them). Figure out all of your dimensions for each box/ region ahead of time.
Collect all of your dimensions and color hex values into an info file (I use a txt file) that you can easily reference. This will reduce your alt-tab tax and selecting colors in Photoshop multiple times.
After all my Guides are in place, I slice out the entire website into my images folder, starting with photos and grouped elements, and ending with the various background tiles/images, should they exist. (Tip: Use ctrl-click on the layer preview to select that layer's content).
Notes on using Photoshop:
Use Guides or the Grid.
Use the Notes feature for any pertinent information
Always use Layer Groups for similar elements. We need to be able to turn entire regions off in one click. Put all 'header' content in one Layer Group.
Always name your layers.
You can put each page template in one PSD file and use nested Layer Groups to organize them. This way we don't have to setup all of our guides and notes for each page template on a site.
No shortcuts :) but everybody works slightly differently.
This tutorial that popped up in my feedreader yesterday shows the process from start to finish and might help people who have never done it before but as you are an old hand it's just about streamlining your own methods.
EDIT:
The listapart link certainly is more automated for 'flat' designs where both imageready and fireworks have had pretty good support from day one and it's got better and more semantic with every release but if you have a more complex design it's the twiddly bits that make the design what it is and these have to be done by hand.
I just thought it was worth pointing out that in addition to the excellent advice you've had so far I'd recommend getting a printed version of the design, using a red pen to mark up all the block elements on the design you think you can spot and sitting down with the designer for half an hour and talking through how they envisioned their design working for the use cases that don't fit the static design.
What happens when more text is put in the navigation?
Is this width fixed or fluid?
Is this content pane to the right fixed height or fluid? If it's fluid why did you put a background on it that can't be repeated?
You have a border extending down the page that breaks two otherwise connected elements. Visually it makes sense, but semantically I not can't just use an li to house both those elements. What do you think is more important?
It'll also help you spot potential problems that you might otherwise not have realised were going to be issues until your elbow deep in css.
Not only does it make your job easier after a few times doing it your designer will get a much stronger sense of what is involved in marking up their work - some designers have real trouble comprehending why something they think looks visually very simple will take a few days of css tweaking to make work.
Some of the designers i know, usually uses Illustrator to make the design elements.
This page shows how to do it a little more automated.
Also, get to know the "Layer Comps" feature. I use this for changing button states.
Create layer comps for normal, hover, and active.
In each of these, set up the effects/color overlays and visible layers which belong with that state.
Save for web: go to a different folder for each state, unless it's easier to rename each slice (otherwise your hover button slices will overwrite your regular slices).