How to Override width and height HTML attributes with CSS

By  on  

One of the HTML elements that frequently comes into collision with CSS is the img element. As we learned in Request Metrics' Fixing Cumulative Layout Shift Problems on DavidWalshBlog article, providing image dimensions within the image tag will help to improve your website's score. But in a world where responsive design is king, we need CSS and HTML to work together.

Most responsive design style adjustments are done via max-width values, but when you provide a height value to your image, you can get a distorted image. The goal should always be a display images in relative dimensions. So how do we ensure the height attribute doesn't conflict with max-width values?

The answer is as easy as height: auto!

/* assuming any media query */
img {
  /* Ensure the image doesn't go offscreen */
  max-width: 500px;
  /* Ensure the image height is responsive regardless of HTML attribute */
  height: auto;
}

The dance to please users and search engines is always a fun balance. CSS and HTML were never meant to conflict but in some cases they do. Use this code to optimize for both users and search engines!

Recent Features

  • By
    Responsive and Infinitely Scalable JS Animations

    Back in late 2012 it was not easy to find open source projects using requestAnimationFrame() - this is the hook that allows Javascript code to synchronize with a web browser's native paint loop. Animations using this method can run at 60 fps and deliver fantastic...

  • By
    How I Stopped WordPress Comment Spam

    I love almost every part of being a tech blogger:  learning, preaching, bantering, researching.  The one part about blogging that I absolutely loathe:  dealing with SPAM comments.  For the past two years, my blog has registered 8,000+ SPAM comments per day.  PER DAY.  Bloating my database...

Incredible Demos

  • By
    Control Element Outline Position with outline-offset

    I was recently working on a project which featured tables that were keyboard navigable so obviously using cell outlining via traditional tabIndex=0 and element outlines was a big part of allowing the user navigate quickly and intelligently. Unfortunately I ran into a Firefox 3.6 bug...

  • By
    JavaScript Copy to Clipboard

    "Copy to clipboard" functionality is something we all use dozens of times daily but the client side API around it has always been lacking; some older APIs and browser implementations required a scary "are you sure?"-style dialog before the content would be copied to clipboard -- not great for...

Discussion

    Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!