Better add images through html or css?

Better add images through html or css? - html

Better add images through HTML and determine alt tags, or add through CSS with the text-indent: -9999px (or similar) property? Or is there no difference?
Does search engines take text-indent: -9999px property as a normal way of doing things? Cause with this property we actually create a text, but not showing it for the user.

I'd say it depends on what you're trying to make it mean. Is it an image with text fallback, or is it text with an image enhancement?
If I have an image which is just a fancier version of the text (perhaps with special effects or flourishes), I use the text with background-image and negative text-indent. If I have an image where the text does not convey the full meaning, I use <img alt>.

Related

How to define alternate text for link button? [duplicate]

This is one I have not had to tackle before. I need to use alt tags on all images in a site including those used by CSS background-image attribute.
There is no CSS property like this as far as I know, so what is the best way to do this please?

Background images sure can present data! In fact, this is often recommended where presenting visual icons is more compact and user-friendly than an equivalent list of text blurbs. Any use of image sprites can benefit from this approach.
It is quite common for hotel listings icons to display amenities. Imagine a page which listed 50 hotel and each hotel had 10 amenities. A CSS Sprite would be perfect for this sort of thing -- better user experience because it's faster. But how do you implement ALT tags for these images? Example site.
The answer is that they don't use alt text at all, but instead use the title attribute on the containing div.
HTML
<div class="hotwire-fitness" title="Fitness Centre"></div>
CSS
.hotwire-fitness {
float: left;
margin-right: 5px;
background: url(/prostyle/images/new_amenities.png) -71px 0;
width: 21px;
height: 21px;
}
According to the W3C (see links above), the title attribute serves much of the same purpose as the alt attribute
Title
Values of the title attribute may be rendered by user agents in a variety of ways. For instance, visual browsers frequently display the title as a "tool tip" (a short message that appears when the pointing device pauses over an object). Audio user agents may speak the title information in a similar context. For example, setting the attribute on a link allows user agents (visual and non-visual) to tell users about the nature of the linked resource:
alt
The alt attribute is defined in a set of tags (namely, img, area and optionally for input and applet) to allow you to provide a text equivalent for the object.
A text equivalent brings the following benefits to your website and its visitors in the following common situations:
nowadays, Web browsers are available in a very wide variety of platforms with very different capacities; some cannot display images at all or only a restricted set of type of images; some can be configured to not load images. If your code has the alt attribute set in its images, most of these browsers will display the description you gave instead of the images
some of your visitors cannot see images, be they blind, color-blind, low-sighted; the alt attribute is of great help for those people that can rely on it to have a good idea of what's on your page
search engine bots belong to the two above categories: if you want your website to be indexed as well as it deserves, use the alt attribute to make sure that they won't miss important sections of your pages.

In this Yahoo Developer Network (archived link) article it is suggested that if you absolutely must use a background-image instead of img element and alt attribute, use ARIA attributes as follows:
<div role="img" aria-label="adorable puppy playing on the grass">
...
</div>
The use case in the article describes how Flickr chose to use background images because performance was greatly improved on mobile devices.

I think you should read this post by Christian Heilmann. He explains that background images are ONLY for aesthetics and should not be used to present data, and are therefore exempt from the rule that every image should have alternate-text.
Excerpt (emphasis mine):
CSS background images which are by definition only of aesthetic value
– not visual content of the document itself. If you need to put an
image in the page that has meaning then use an IMG element and give it
an alternative text in the alt attribute.
I agree with him.

As mentioned in other answers, there is no (supported) alt attribute for a div tag only for the img tag.
The real question is why you need to add the alt attribute to all background images for the site? Based on this answer, it will help you determine which route to take in your approach.
Visual/Textual: If you are simply attempting to add a textual fall back for the user if the image fails to load, simply use the title attribute. Most browsers will provide a visual tool tip(message box) when a user hovers over the image, and if the image is not loaded for whatever reason, it behaves the same as an alt attribute presenting text when image fails. This technique still allows for the site to speed up load times by keeping images set to backgrounds.
Screen Readers: The middle of the road option, this varies because technically keeping your images as backgrounds and using the title attribute approach should work as hinted above, "Audio user agents may speak the title information in a similar context." However this is not guaranteed to work in all cases, including some readers may ignore it all together. If you end up opting for this approach, you can also try adding in aria-labels to help ensure screen readers pick these up.
SEO/Search Engines: Here is the big one, if you were like me, you added your background images, all was good. Then months later the customer(or maybe yourself) realized that you are missing out on some prime SEO gold by not having alt's for your images. Keep in mind, the title attribute does not have any weight on search engines, from my research and as mentioned in an article here: https://www.searchenginejournal.com/how-to-use-link-title-attribute-correctly/. So if you are aiming for SEO, then you will need to have an img tag with the alt attribute. One possible approach is to just load very small actual images on the site with alt attributes, this way you get all the SEO and don't have to readjust the existing CSS in place. However this may lead to additional load time depending on the size and google does indeed look at the images path when indexing. In short if you are going this route, just accept what has to be done and include the actual images instead of using backgrounds.

The general belief is that you shouldn't be using background images for things with meaningful semantic value so there isn't really a proper way to store alt data with those images. The important question is what are you going to be doing with that alt data? Do you want it to display if the images don't load? Do you need it for some programmatic function on the page? You could store the data arbitrarily using made up css properties that have no meaning (might cause errors?) OR by adding in hidden images that have the image and the alt tag, and then when you need a background images alt you can compare the image paths and then handle the data however you want using some custom script to simulate what you need. There's no way I know of to make the browser automatically handle some sort of alt attribute for background images though.

This article from W3C tells you what they think you should do
https://www.w3.org/WAI/GL/wiki/ARIATechnique_usingImgRole_with_aria-label_forCSS-backgroundImage
and has examples here
http://mars.dequecloud.com/demo/ImgRole.htm
among which
<a href="http://www.facebook.com">
<span class="fb_logo" role="img" aria-label="Connect via Facebook">
</span>
</a>
Still, if, like in the above example, the element containing the background image is just an empty container, I personally prefer to put the text in there and hide it using CSS; right where you show the image instead:
<a href="http://www.facebook.com"><span class="fb_logo">
Connect via Facebook
</span></a>
.fb_logo {
height: 37px; width: 37px;
background-image: url('../gfx/logo-facebook.svg');
color:transparent; overflow:hidden; /* hide the text */
}

The classical way to achieve this is to put the text into the div and use an image replacement technique.
<div class"ir background-image">Your alt text</div>
with background-image beeing the class where you assign the background image and ir could be HTML5boilerplates image replacement class, below:
/* ==========================================================================
Helper classes
========================================================================== */
/*
* Image replacement
*/
.ir {
background-color: transparent;
border: 0;
overflow: hidden;
/* IE 6/7 fallback */
*text-indent: -9999px;
}
.ir:before {
content: "";
display: block;
width: 0;
height: 150%;
}

Here's my solution for Immediate fix:
Once the background image is removed the alt text will be visible from Img tag.
.alt-image {
position: absolute;
top: 0;
left: 0;
z-index: -1;
}
.background-image{
background:url("https://www.w3schools.com/images/picture.jpg") no-repeat;
width:100%;
height:500px;
position:relative;
}
<div role="img" aria-label="place alt text here" title="place alt text here" class="background-image">
<img src="" alt="place alt text here" class="alt-image"/>
</div>

Here's my solution to this type of problem:
Create a new class in CSS and position off screen. Then put your alt text in HTML right before the property that calls your background image. Can be any tag, H1, H2, p, etc.
CSS
<style type="text/css">
.offleft {
margin-left: -9000px;
position: absolute;
}
</style>
HTML
<h1 class="offleft">put your alt text here</h1>
<div class or id that calls your bg image> </div>

It''s not clear to me what you want.
If you want a CSS property to render the alt attribute value, then perhaps you're looking for the CSS attribute function for example:
IMG:before { content: attr(alt) }
If you want to put the alt attribute on a background image, then ... that's odd because the alt attribute is an HTML attribute whereas the background image is a CSS property. If you want to use the HTML alt attribute then I think you'd need a corresponding HTML element to put it in.
Why do you "need to use alt tags on background images": is this for a semantic reason or for some visual-effect reason (and if so, then what effect or what reason)?

You can achieve this by putting the alt tag in the div were your image will appear.
Example:
<div id="yourImage" alt="nameOfImage"></div>

Image replacement

I have a large div with the site header/logo as the background image. Is there anything wrong with putting a h2 tag containing the site title behind this using z-index, so that it would show if the user couldn't/didn't get the image for some reason? I know this is different to a standard [background on the h2 element] image replacement. (EDIT: Sorry maybe i'm not making it clear - i'm using a div background image not an IMG tag)

You should use the alt attribute of the img tag, so if the image isn't loaded for some reason, the text would appear.
This is exactly why the alt attr exists,.

If possible, I would ditch the div and just use an h2 with an id and set a background image to that.
I do that whenever possible to avoid excessive divs when I could use other block-level elements, if it only has a background and text. An h* with a background image is still a heading.

You can simple place img tag with alt attribute. That way if image is not loaded, text will be displayed.
<img src="" alt="This text will be displayed" />

Google doesn't like what you describe:
http://www.google.com/support/webmasters/bin/answer.py?answer=66353
However, from a pure design perspective, there is no real problem, save some bloated code.
You might want to see how often your images fail before you attempt any changes.

That's fine. Note that many feel the site logo isn't really something you'd put into an h* tag other than on the home page, when it makes sense to put it in an h1 tag.

If the tabs use all images to show text + icon on each tab, then how to add text to to help search engine to find the keywords on the tabs?

Especially each image that contains the text and icon are displayed using background-image in CSS (using CSS Sprites), so there is no even alt or title if the image
had been shown using <img>. So, pure image in this case. How can actual text be added (or using some other mechanism) for search engines to better index these tabs?

You'd use an 'image replacement technique':
http://www.mezzoblue.com/tests/revised-image-replacement/

Just use actual relevant text in each element and use text-indent:-9999em; to shift it offscreen. This may involve extra styling such as display:block on the element if it's normally inline for text-indent to work but you'll end up with basic a CSS image replacement implementation.

You should absolutely be using text somewhere, at least an alt tag.
Try a something like <span>Text</span> with text-indent:-9999px;, or any of the other variations of css text hiding/masking.
There may be some merit to adding the title attribute to those tabs as well.

If you use a <span> and set its display to none via CSS, then you can put whatever text in there you like for SEO.
This is done on i.e. <h3> tags on the css Zen garden. A number of them use this construct:
<h3>
<span>The Road to Enlightenment</span>
</h3>
...where you then give the <h3> a CSS background-image and set the <span>'s display to none. You should be able to use the same type of idea for tabs that use images.

CSS background image alt attribute

This is one I have not had to tackle before. I need to use alt tags on all images in a site including those used by CSS background-image attribute.
There is no CSS property like this as far as I know, so what is the best way to do this please?

In this Yahoo Developer Network (archived link) article it is suggested that if you absolutely must use a background-image instead of img element and alt attribute, use ARIA attributes as follows:
<div role="img" aria-label="adorable puppy playing on the grass">
...
</div>
The use case in the article describes how Flickr chose to use background images because performance was greatly improved on mobile devices.

I think you should read this post by Christian Heilmann. He explains that background images are ONLY for aesthetics and should not be used to present data, and are therefore exempt from the rule that every image should have alternate-text.
Excerpt (emphasis mine):
CSS background images which are by definition only of aesthetic value
– not visual content of the document itself. If you need to put an
image in the page that has meaning then use an IMG element and give it
an alternative text in the alt attribute.
I agree with him.

The general belief is that you shouldn't be using background images for things with meaningful semantic value so there isn't really a proper way to store alt data with those images. The important question is what are you going to be doing with that alt data? Do you want it to display if the images don't load? Do you need it for some programmatic function on the page? You could store the data arbitrarily using made up css properties that have no meaning (might cause errors?) OR by adding in hidden images that have the image and the alt tag, and then when you need a background images alt you can compare the image paths and then handle the data however you want using some custom script to simulate what you need. There's no way I know of to make the browser automatically handle some sort of alt attribute for background images though.

This article from W3C tells you what they think you should do
https://www.w3.org/WAI/GL/wiki/ARIATechnique_usingImgRole_with_aria-label_forCSS-backgroundImage
and has examples here
http://mars.dequecloud.com/demo/ImgRole.htm
among which
<a href="http://www.facebook.com">
<span class="fb_logo" role="img" aria-label="Connect via Facebook">
</span>
</a>
Still, if, like in the above example, the element containing the background image is just an empty container, I personally prefer to put the text in there and hide it using CSS; right where you show the image instead:
<a href="http://www.facebook.com"><span class="fb_logo">
Connect via Facebook
</span></a>
.fb_logo {
height: 37px; width: 37px;
background-image: url('../gfx/logo-facebook.svg');
color:transparent; overflow:hidden; /* hide the text */
}

The classical way to achieve this is to put the text into the div and use an image replacement technique.
<div class"ir background-image">Your alt text</div>
with background-image beeing the class where you assign the background image and ir could be HTML5boilerplates image replacement class, below:
/* ==========================================================================
Helper classes
========================================================================== */
/*
* Image replacement
*/
.ir {
background-color: transparent;
border: 0;
overflow: hidden;
/* IE 6/7 fallback */
*text-indent: -9999px;
}
.ir:before {
content: "";
display: block;
width: 0;
height: 150%;
}

Here's my solution for Immediate fix:
Once the background image is removed the alt text will be visible from Img tag.
.alt-image {
position: absolute;
top: 0;
left: 0;
z-index: -1;
}
.background-image{
background:url("https://www.w3schools.com/images/picture.jpg") no-repeat;
width:100%;
height:500px;
position:relative;
}
<div role="img" aria-label="place alt text here" title="place alt text here" class="background-image">
<img src="" alt="place alt text here" class="alt-image"/>
</div>

Here's my solution to this type of problem:
Create a new class in CSS and position off screen. Then put your alt text in HTML right before the property that calls your background image. Can be any tag, H1, H2, p, etc.
CSS
<style type="text/css">
.offleft {
margin-left: -9000px;
position: absolute;
}
</style>
HTML
<h1 class="offleft">put your alt text here</h1>
<div class or id that calls your bg image> </div>

It''s not clear to me what you want.
If you want a CSS property to render the alt attribute value, then perhaps you're looking for the CSS attribute function for example:
IMG:before { content: attr(alt) }
If you want to put the alt attribute on a background image, then ... that's odd because the alt attribute is an HTML attribute whereas the background image is a CSS property. If you want to use the HTML alt attribute then I think you'd need a corresponding HTML element to put it in.
Why do you "need to use alt tags on background images": is this for a semantic reason or for some visual-effect reason (and if so, then what effect or what reason)?

You can achieve this by putting the alt tag in the div were your image will appear.
Example:
<div id="yourImage" alt="nameOfImage"></div>

HTML text over images for buttons?

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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