You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
A validator is a program that checks for syntax errors in code. Validators can be created for any format or language, but in our context we speak of tools that check {{Glossary("HTML")}}, {{Glossary("CSS")}}, and {{Glossary("XML")}}.
## See also
- [Validator](https://en.wikipedia.org/wiki/Validator) on Wikipedia
- [Short list of validators](https://firefox-source-docs.mozilla.org/devtools-user/validators/index.html)