# Bad value X for attribute “href” on element “a”: Illegal character in path segment. “|” is not allowed.

> Canonical HTML version: https://rocketvalidator.com/html-validation/bad-value-x-for-attribute-href-on-element-a-illegal-character-in-path-segment-pipe-is-not-allowed
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

The `href` value on the `<a>` element contains a literal `|` (pipe) character, which is not allowed in a URL path.

The URL standard doesn't list `|` among the characters a URL can contain, so a pipe in the path has to be written as `%7C`. Browsers still follow the link, but the markup is invalid.

This usually comes from a CMS or template that builds the path from a page title. A title like "Summer concert | Tickets" uses the pipe as a separator. If the slug function only lowercases the text and turns spaces into hyphens, the `|` stays and the path ends up as `summer-concert-|-tickets`. Fix the slug function so it drops anything other than letters, digits and hyphens. The new slug gives the page a new address, so redirect the old URL to it. If the URLs can't change, write the pipe as `%7C` in the `href` instead.

When the `href` is very long, the validator leaves the value out of the message. The cause and the fix are the same.

## Invalid example

```html
<a href="/events/42/summer-concert-|-tickets">Summer concert | Tickets</a>
```

## Valid example

Remove the pipe from the slug:

```html
<a href="/events/42/summer-concert-tickets">Summer concert | Tickets</a>
```

If the URL has to stay the same, percent-encode the pipe:

```html
<a href="/events/42/summer-concert-%7C-tickets">Summer concert | Tickets</a>
```