[html] Can I style an image's ALT text with CSS?

I have a dark blue page and when the image is loading (or missing) the ALT text is black and difficult to read (in FF).

Could I style it (with CSS) to be white?

Sure you can!

http://jsfiddle.net/VfTGW/

I do this as a fallback for header logo images, I think some versions of IE will not abide. Edit: Or Chrome apparently - I don't even see alt text in the demo(?). Firefox works well however.

img {_x000D_
  color: green;_x000D_
  font: 40px Impact;_x000D_
}

<img src="404" alt="Alt Text">

as this question is the first result at search engines

There are a problem with the selected -and right by the way- solution, is that if you want to add style that will apply to images like ( borders for example ) .

for example :

img {_x000D_
  color:#fff;_x000D_
  border: 1px solid black;_x000D_
  padding: 5px;_x000D_
  background-color: #ccc;_x000D_
}

<img src="http://badsrc.com/blah" alt="BLAH BLAH BLAH" /> <hr />_x000D_
<img src="https://cdn4.iconfinder.com/data/icons/miu-square-flat-social/60/stackoverflow-square-social-media-128.png" alt="BLAH BLAH BLAH" />

as you can see, all of images will apply the same style

there is another approach to easily work around such an issue, using onerror and injecting some special class to deal with the interrupted images :

.invalidImageSrc {_x000D_
  color:#fff;_x000D_
  border: 1px solid black;_x000D_
  padding: 5px;_x000D_
  background-color: #ccc;_x000D_
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>_x000D_
_x000D_
<img onerror="$(this).addClass('invalidImageSrc')" src="http://badsrc.com/blah" alt="BLAH BLAH BLAH" /> <hr />_x000D_
<img onerror="$(this).addClass('invalidImageSrc')" src="https://cdn4.iconfinder.com/data/icons/miu-square-flat-social/60/stackoverflow-square-social-media-128.png" alt="BLAH BLAH BLAH" />

You can use img[alt] {styles} to style only the alternative text.

In Firefox and Chrome (and possibly more) we can insert the string ‘( .... )’ into the alt text of an image that hasn’t loaded.

img {_x000D_
  font-style: italic;_x000D_
  color: #c00;_x000D_
}_x000D_
_x000D_
img:after {_x000D_
  content: " (Image - Right click to reload if not loaded)";_x000D_
}_x000D_
_x000D_
img::after {_x000D_
  content: " (Image - Right click to reload if not loaded)";_x000D_
}

<img alt="Alt text - " />

You cant style the alt attribute directly in css. However the alt will inherit the styles of the item the alt is on or what is inherited by its parent:

    <div style="background-color:black; height: 50px; width: 50px; color:white;">_x000D_
    <img src="ouch" alt="here i am"/>_x000D_
    <div>

In the above example, the alt text will be black. However with the color:white the alt text is white.

Yes, image alt text can be styled using any style property you use for regular text, such as font-size, font-weight, line-height, color, background-color,etc. The line-height (of text) or vertical-align (if display:table-cell used) could also be used to vertically align alt text within an image element or image wrapping container, i.e. div.

To prevent accessibility issues regarding contrast, and inheriting the browser's default black font color when you've set a dark blue background-color, always set both the color of your font and its background-color at the same time.

for some more useful info, visit Alternate text for background images or The Ultimate Guide to Styled ALT Text in Email