# Unescaped '<' not allowed in attributes values

Source: https://xmlvalid.com/errors/unescaped-less-than-in-attribute

> A &lt; character inside an attribute value.

Example message: `Unescaped '<' not allowed in attributes values`

## Why it happens

- A comparison or markup kept in an attribute: `test="a < b"`, `title="<b>bold</b>"`.
- A missing closing quote on the previous attribute, so the next tag seems to be inside the value.

## How to fix it

- Write `&lt;` instead of `<` inside attribute values. If the cause is a missing quote, the line of the error is usually just after it.

## Example that fails

```xml
<rule test="a < b"/>
```

## Fixed

```xml
<rule test="a &lt; b"/>
```