In the Name of Accessibility: Check Your Alt Attributes!

Occasionally I am browsing the net with images switched off because I am only interested in the text and don’t want to download gigantic amounts of decorative images – especially since several pages started to use HDPI images which are 4 times the size needed and thus HUGE downloads – and I noticed that seemingly some authors are not aware that they are missing an important accessibility feature, that exists since about the web was invented:

The alt attribute on images.

While people who don’t switch off image loading or can see well and don’t need to use assistive technologies like e.g. screen readers to get hold of the content, users who don’t or can’t display images for various reasons are at loss in such a situation, so please, dear web developers, check if all of your non-decorative images have those alt attributes.

An easy way is to temporarily overwrite the page styles with the following stylesheet:

html::before {
    content: "All visible images are either missing alt attributes or the alt attributes don't follow the specification!" !important;
    font-family: sans-serif !important;
    font-size: 20px !important;
    font-weight: bold !important;
    text-align: center !important;
    color: #F8F8F8 !important;
    background-color: #EE3333 !important;
    padding: 5px 0 !important;
    margin: 0 !important;
    border: none !important;
    width: 100% !important;
    float: none !important;
    position: static !important;
    display: inline-block !important;
html {
    color: #202020 !important;
    background-color: #F8F8F8 !important;
    padding: 0 !important;
    margin: 0 !important;
    border: none !important;
    width: auto !important;
    max-width: none !important;
    display: block !important;
html * {
    visibility: hidden !important;
html area,
html img {
    visibility: visible !important;
html area[alt],
html img[alt] {
    visibility: hidden !important;
html area[alt="*"],
html area[alt=""],
html img[alt="*"],
html img[alt=""],
html img[alt^=" "] {
    outline: 4px solid rgb(51, 102, 204) !important;
    visibility: visible !important;

You might need to adapt it if you use a Styling Extension, this is written for direct use in Vivaldi.

In Vivaldi you can add this as page action. Just save it as Image_Alt_Debugger.css to [path to]\Application\#.#.###.##\resources\vivaldi\user_files and after the next browser restart you will see the Entry “Image Alt Debugger” in the list of page actions. (Hint: Underscores in the name get replaced by Spaces for display)


PS: Sadly you have to do that for each and every update of Vivaldi because or some unknown reason they put this stuff into the Application directory instead of the User Data directory.

2 replies on “In the Name of Accessibility: Check Your Alt Attributes!”

  1. You can add this stylesheet into Stylish but i think without html * {visibility: hidden !important;}

  2. Warning: Don’t use this in Stylish or similar extensions! You will not see the settings page anymore!

    This stylesheet is meant for debugging purposes and hides all content that is not images without or with incorrect alt attributes – including the Stylish settings page.

    If you want to use it in the context of an extension, you need to adapt it to your needs.

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