Ensures <meta name="viewport"> Does Not Disable Text Scaling and Zooming

An HTML document must not use the user-scalable=”no” parameter in the <meta name=”viewport”> element because it disables text scaling and zooming.

Why It Matters

The user-scalable=”no” parameter inside the content attribute of <meta name=”viewport”> element disables zooming on a page. This will create issues for people with low vision who rely on screen magnifiers.

Users with partial vision and low vision often need to enlarge the fonts on their browser to make text easier to read. 

If the browser window is small, the viewport focus area only includes a certain portion of a web page. The browser’s viewport focus does not affect the programmatic focus. Users can scroll up and down the web page, but the programmatic focus does not follow the viewport. 

Fixing the Issue

Remove the user-scalable=”no” parameter from the content attribute of the <meta name=”viewport”> element in order to allow zooming and ensure the maximum-scale parameter is not less than 2.

A meta viewport element tells the browser how to control the page’s dimensions and to scale, but the ability to zoom can be disabled as a result of its use.

Test Cases

For more examples, visit the W3C’s GitHub’s ATC Rules library.