<ul> and <ol> must only directly contain <li>, <script> or <template> elements
How to Fix the Problem
Ensure all ordered and unordered lists (defined by
ol elements) contain only
li content elements.
Here is a list, using proper semantic markup:
<p> These are a few of my favorite things</p> <ul> <li>Raindrops on roses</li> <li>Whiskers on kittens</li> <li>Bright copper kettles</li> <li>Warm woolen mittens</li> <li>Brown paper packages tied up with strings</li> <li>Cream colored ponies</li> <li>Crisp apple streudels</li> <li>Doorbells and sleigh bells</li> <li>Schnitzel with noodles</li> <li>Wild geese that fly with the moon on their wings</li> <li>Girls in white dresses with blue satin sashes</li> <li>Snowflakes that stay on my nose and eyelashes</li> <li>Silver white winters that melt into springs</li> </ul>
Why it Matters
Screen readers have a specific way of announcing lists. This feature makes lists clearer to understand, but will only work if lists are properly structured.
When content elements other than list items are contained within a set of list elements, screen readers cannot inform the listener that they are listening to items within the list.
For a list to be valid, it must have both parent elements (a set of
ul elements or a set of
ol elements) and child elements (declared inside of these tags using the
li element), and any other content elements are invalid.
Although some non-content elements such as script, template, style, meta, link, map, area, and datalist are permitted within lists, content elements other than
li are not permitted.
Lists must be marked up correctly, meaning they must not contain content elements other than
The Algorithm (in simple terms)
Ensures that lists are structured correctly.